Adhesive composition and masking article for producing precise paint lines

ABSTRACT

An adhesive article for masking a portion of a substrate surface from a liquid coating applied to the surface includes a support having first and second opposed major surfaces, and a cationic or zwitterionic adhesive composition disposed on at least a portion of at least one of the first and second opposed major surfaces. The adhesive composition provides a barrier that impedes the migration of the coating past the edge of the adhesive article.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. utility patentapplication Ser. No. 14/102258, filed Dec. 10, 2013, which claims thebenefit of U.S. Provisional Patent Application No. 61/737225, filed Dec.14, 2012, the disclosures of which are incorporated by reference herein.

BACKGROUND

The present disclosure relates generally to masking articles, such asmasking tape, and, more particularly, to a masking article that producesprecise paint lines, and to adhesive compositions for making maskingarticles.

When applying a surface coating, such as paint or stain, to a surface,care must be taken so that the paint does not get on the surfacesadjacent to the surface to be painted. This can be accomplished bycarefully painting the surface, or by masking off the area around thesurface to be painted. Masking articles, such as masking tapes andadhesive masking sheets, are often used to protect the area adjacent tothe surface being painted. When using such masking articles, it isgenerally desirable that the paint not bleed past the demarcation linedefined by the edge of the masking article. In this manner, the maskingarticle will produce a paint line between the painted surface andunpainted surface that is smooth and consistent, and precisely matchesthe line intended by the user. Depending on a number of factors, such ashow well such masking articles are applied to the surface, the energy ofthe surface, and the texture of the surface to which such maskingarticles are applied, paint may flow beyond the edge of the maskingarticle and under certain regions of the masking article, therebyproducing an imprecise paint line.

Adhesive tapes and masking materials having an edge coating forimproving the masking ability of the materials are known in the priorart. U.S. Pat. No. 6,828,008 (Gruber), for example, discloses anabsorbent edge coating for masking tape and other masking materials. Themasking tape comprises a substrate having a top surface, a bottomsurface, and at least one masking edge. The bottom surface of thesubstrate has an adhesive layer applied thereto. An absorbent edgecoating is applied to at least one masking edge of the substrate so asto at least substantially prevent liquids addressed to the at least onecoated masking edge from being absorbed into the substrate of the tapeand from passing between the bottom surface of the tape and a surface towhich the tape has been applied.

U.S. Patent Publication No. 2010/0307411 discloses an adhesive maskingarticle for shielding a protected work surface from a coating applied toa surface adjacent the protected work surface, the masking articleincluding a backing layer having first and second opposed majorsurfaces, and at least one edge. The masking article has an adhesive onat least a portion of at least one of the first and second backing layeropposed major surfaces and a water soluble cationic barrier inducingcompound present on at least the edge of the masking article. Thecationic compound contacts the coating when the coating comes intocontact with the edge of the backing layer and destabilizes the coating,thereby producing a barrier effect. Previous attempts to develop maskingarticles that impede the migration of paint past the edge of the maskingarticle suffer from a number of drawbacks and disadvantages. Forexample, known adhesive masking articles may include the use ofingredients that are difficult to apply to the masking article duringthe manufacturing process, may require expensive packaging to maintaintheir effectiveness, may be harmful if ingested, and/or may cause skin,eye and nose irritation, which may require warnings and/or specialhandling instructions, or may produce unintended and undesirable effectsat either the interface of the masking article and the paint, or on thesurface to be painted.

Masking articles can include superabsorbent polymers (SAPs), such assodium polyacrylate, as edge treatments. In addition, because of theirabsorbency, when masking articles including superabsorbent polymers areused in paint masking applications, an undesirable raised region, orridge, of paint is often created along the edge of the masking article.This raised region generally takes longer to dry, and is therefore moresusceptible to damage prior to fully drying. In addition, loose orexcess SAP may fall onto the surface to be painted. SAP on the surfaceto be painted may, in turn, interfere with the application of paint tothe surface (i.e., it may create an unsightly blotchy appearance in thepaint).

Additionally, masking articles, such as adhesive tapes, having an edgecoating suffer from certain inherent disadvantages. First, when a userdivides the article, e.g., tears off a piece of tape, the new edgecreated by the division does not have the edge coating for preventingflow of paint beyond the edge of the masking article. Second, providingedge coatings necessitates a separate processing step in making thearticle or tape. Third, edge coatings almost inevitably causedifferences in adhesion of the article to a given substrate at the edgevs. the remainder of the article. Increased adhesion can causedifficulty in removing the article from the substrate after paint isapplied, can cause residual materials to be left on the substrate afterremoval, or both. Decreased adhesion can lead to egress of the paintduring coating. A related issue is that edge coatings may suffer fromlack of adhesion to the article itself, and may flake off,preferentially adhere to the substrate on which the article is applied,or otherwise depart from the article and thereby fail to provide theintended protection. Fourth, edge coatings represent a separate and, insome cases costly, additional step in processing. A related issue isthat edge coatings are highly impractical to manufacture in any form buta straight-edged product, such as a tape. Manufacturing of maskingarticles such as stencils or other non-linear shapes is impracticableusing edge-coating technology.

The need exists for adhesive masking articles that address the abovelisted limitations. Additionally, the need exists for an adhesivemasking article for paint masking that is easy to make, does not requirespecial packaging, is safe and easy to use, and produces sharp, clean,precise, smooth, even paints lines. The terms “sharp”, “clean”,“precise”, “smooth” and “even”, when used to describe a paint line,generally refer to a paint line that corresponds to and is defined bythe edge of the masking article. That is, a sharp, clean, precise,smooth, or even paint line is one in which the paint does not extendsignificantly beyond the edge of the masking article so as to penetrateunder the masking article. Thus, a “sharp”, “clean”, “smooth”, or “even”paint line has minimal or no paint bleed under the article (i.e., littleor no paint flow between the masking article and masked surface).

SUMMARY

In some embodiments, the present disclosure provides an adhesivecomposition including a polymer, the polymer consisting essentially ofthe polymerized product of about 0 wt % to 5 wt % based on the totalweight of the polymer of a carboxylate salt of acrylic acid ormethacrylic acid, or a mixture of two or more thereof, wherein theamount of carboxylate salt is determined based on the weight of thecorresponding free acid; about 50 wt % to 95 wt % based on the totalweight of the polymer of an acrylate or methacrylate ester of an alcoholhaving between 8 and 12 carbons; about 2 wt % to 45 wt % based on thetotal weight of the polymer of an acrylate or methacrylate esterincluding an alkylammonium functionality; and about 0 wt % to 30 wt %based on the total weight of the polymer of an additional monomer.

In some embodiments, the present disclosure provides an adhesive articleincluding a support having first and second opposed major surfaces andan adhesive composition disposed on at least a portion of at least oneof the first and second opposed major surfaces, wherein the adhesivecomposition includes a polymer, the polymer consisting essentially ofthe polymerized product of about 0 wt % to 5 wt % based on the totalweight of the polymer of a carboxylate salt of acrylic acid ormethacrylic acid, or a mixture of two or more thereof, wherein theamount of carboxylate salt is determined based on the weight of thecorresponding free acid; about 50 wt % to 95 wt % based on the totalweight of the polymer of an acrylate or methacrylate ester of an alcoholhaving between 8 and 12 carbons; about 2 wt % to 45 wt % based on thetotal weight of the polymer of an acrylate or methacrylate esterincluding an alkylammonium functionality; and about 0 wt % to 30 wt %based on the total weight of the polymer of an additional monomer. Insome embodiments, the article is a masking tape. In some embodiments,the article is a stenciling article.

In some embodiments, the present disclosure provides method of making amasking article wherein the article is capable of substantiallypreventing one or more liquids or liquid-borne materials from contactinga masked surface, the method including

forming a reaction mixture including about 15 wt % to 60 wt % monomersin water, wherein the monomers consist essentially of about 0 parts byweight to 5 parts by weight of acrylic acid, methacrylic acid, or acombination of two or more thereof; about 50 parts by weight to 95 partsby weight based on the total weight of the polymer of an acrylate ormethacrylate ester of an alcohol having between 8 and 12 carbons; about2 parts by weight to 45 parts by weight based on the total weight of thepolymer of an acrylate or methacrylate ester including an alkylammoniumfunctionality; and about 0 parts by weight to 30 parts by weight basedon the total weight of the polymer of an additional monomer;polymerizing the monomers to form a polymerized mixture, adjusting thepH of the polymerized mixture from 2-3 to 4-7 to form a neutralizedmixture, coating the neutralized mixture onto a support, and drying thecoated neutralized mixture.

In embodiments, the adhesive articles of the invention are characterizedby their performance as pressure sensitive adhesives that prevent one ormore liquids or liquid-borne materials from penetrating the interface ofthe adhesive composition and the substrate onto which an adhesivearticle is applied.

Additional advantages and novel features of the invention will be setforth in part in the description that follows, and in part will becomeapparent to those skilled in the art upon examination of the following,or may be learned through routine experimentation upon practice of theinvention.

DETAILED DESCRIPTION

Various embodiments will now be described in detail. Reference tovarious embodiments does not limit the scope of the claims attachedhereto. Additionally, any examples set forth in this specification arenot intended to be limiting and merely set forth some of the manypossible embodiments for the appended claims.

Definitions

As used herein, the term “cationic polymer” or similar terms means apolymer having at least one cationic moiety covalently bonded within apolymer chain, substantially in the absence of anionic moieties alsocovalently bonded within the polymer chain. The cationic moieties aresuitably disposed within the polymer backbone, are pendant to thepolymer backbone, or a mixture thereof. In some embodiments, there is asingle cationically functional monomer covalently bonded within thecationic polymer; in other embodiments there is more than one cationicmoiety covalently bonded within the cationic polymer. In someembodiments, there are one or more nonionic moieties covalently bondedwithin the cationic polymer. In some embodiments the cationic moietiesare randomly distributed within a polymer chain; in other embodimentsthe cationic moieties are present in an alternating pattern, a blockypattern, or another regular or semi-regular pattern within the polymerchain.

As used herein, the term “zwitterionic polymer” or similar terms means apolymer having at least one anionic moiety and at least one cationicmoiety covalently bonded within a single polymer chain. The anionic andcationic moieties are suitably disposed within the polymer backbone, arependant to the polymer backbone, or a mixture thereof. In someembodiments the anionic and cationic moieties are present on the samebackbone or pendant unit; in other embodiments the anionic and cationicmoieties are present on different backbone or pendant units. In someembodiments the anionic and cationic moieties are randomly distributedwithin a polymer chain; in other embodiments the anionic and cationicmoieties are present in an alternating pattern, a blocky pattern, oranother regular or semi-regular pattern within the polymer chain. Insome embodiments the anionic and cationic moieties are present in a 1:1molar ratio within the polymer chain. In other embodiments, the anionicmoieties are present in a molar excess relative to the cationic moietieswithin the polymer chain. In still other embodiments, the cationicmoieties are present in a molar excess relative to the anionic moietieswithin the polymer chain. In some embodiments, there is a singleanionically functional monomer covalently bonded within the zwitterionicpolymer; in other embodiments there is more than one anionicallyfunctional monomer covalently bonded within the zwitterionic polymer. Insome embodiments, there is a single cationically functional monomercovalently bonded within the zwitterionic polymer; in other embodimentsthere is more than one cationically functional monomer covalently bondedwithin the zwitterionic polymer. In some embodiments, there are one ormore nonionic moieties covalently bonded within the zwitterionicpolymer.

As used herein, the terms “polymerizable” or “curable” are applied tothe compounds, also called “monomers”, that are polymerizable and/orcrosslinkable as a result of initiation by thermal decomposition, redoxreaction, or photolysis. Such compounds have at least one a,(3-unsaturated site. In some embodiments, monomers having more than onea, 13 unsaturated site are termed “crosslinkers” but it will beunderstood that the term “monomer” includes, as appropriate in context,compounds having more than one such site.

As used herein, the term “adhesive composition” or like terms means acationic polymer, or a zwitterionic polymer, and optionally one or moreadditional components blended therewith, wherein the adhesivecomposition is a pressure sensitive adhesive composition when suitablyemployed as part of an adhesive article.

As used herein, the term “adhesive article” means a support having anadhesive composition coated thereon. An adhesive article is a maskingarticle, though it is not a requirement that the adhesive article beused in a masking application. Adhesive articles include adhesive tapes,which can be used as a masking tape. Supports are any useful materialcapable of having the adhesive compositions coated thereon for use in apressure sensitive adhesive application.

As used herein, the term “masking” means substantially preventing one ormore liquids or liquid-borne materials from penetrating the interface ofthe adhesive composition and a substrate onto which an adhesive articleis applied. As used herein in context with a masking application, thesubstrate onto which the adhesive article is applied is a “maskedsubstrate.” As used herein in context with a masking application, theportion of the substrate surface covered by the adhesive article and incontact with the adhesive composition is the “masked surface.” Maskingis achieved when one or more liquids or liquid-borne materials appliedto the masked substrate are substantially prevented from contacting themasked surface.

As used herein, the term “substantial” or “substantially” means withrelatively minor fluctuations or aberrations from the stated property,value, range of values, content, formula, and the like, and does notexclude the presence of additional materials, broader range values, andthe like which do not materially affect the desired characteristics of agiven composition, article, product, or method.

Cationic or Zwitterionic Polymers

The cationic polymers of the invention are copolymers including thepolymerized product of polymerizable monomers including at least anacrylate or methacrylate ester of an alcohol having between 8 and 12carbons and a cationic monomer that is an acrylate or methacrylate esterhaving an alkylammonium functionality. Optionally, one or moreadditional monomers are included in the cationic polymers of theinvention. In some embodiments, the acrylate or methacrylate ester is amixture of two or more such esters; in some embodiments, the cationicmonomer is a mixture of two or more such cationic monomers.

In embodiments, the acrylate or methacrylate ester of an alcohol havingbetween 8 and 12 carbons includes acrylate or methacrylate esters oflinear, branched, or cyclic alcohols. While not intended to be limiting,examples of alcohols useful in the acrylate or methacrylate estersinclude octyl, isooctyl, nonyl, isononyl, decyl, undecyl, and dodecylalcohol. In embodiments, the alcohol is isooctyl alcohol. In someembodiments, the acrylate or methacrylate ester of an alcohol havingbetween 8 and 12 carbons is a mixture of two or more such compounds. Inembodiments, polymerized product of the acrylate or methacrylate esterof an alcohol having between 8 and 12 carbons is present in the cationicpolymer at about 50 wt % to 95 wt % of the total weight of the polymer,or at about 60 wt % to 90 wt % of the total weight of the polymer, or atabout 75 wt % to 85 wt % of the total weight of the polymer, or invarious intermediate levels such as 51 wt %, 52 wt %, 53 wt %, 54 wt %,and all other such values individually represented by 1 wt % incrementsbetween 50 wt % and 95 wt %, and in any range spanning between any ofthese individual values in 1 wt % increments, for example ranges such asabout 54 wt % to 81 wt %, about 66 wt % to 82 wt %, about 77 wt % to 79wt %, and the like.

In embodiments, the cationic monomer is an acrylate or methacrylateester including an alkylammonium functionality. In some embodiments, thecationic monomer is a 2-(trialkyl ammonium)ethyl acrylate or a2-(trialkylammonium)ethyl methacrylate. In such embodiments, the natureof the alkyl groups is not particularly limited; however, cost andpracticality limit the number of useful embodiments. In embodiments, the2-(trialkyl ammonium)ethyl acrylate or 2-(trialkylammonium)ethylmethacrylate is formed from the reaction of 2-(dimethylamino)ethylacrylate or 2-(dimethylamino)ethyl methacrylate with an alkyl halide; insuch embodiments, at least two of the three alkyl groups of the2-(trialkyl ammonium)ethyl acrylate or 2-(trialkylammonium)ethylmethacrylate are methyl. In some such embodiments, all three alkylgroups are methyl groups. In other embodiments, two of the three alkylgroups are methyl and the third is a linear, branched, cyclic, oralicyclic group having between 2 and 24 carbon atoms, or between 6 and20 carbon atoms, or between 8 and 18 carbon atoms, or 16 carbon atoms.In some embodiments, the cationic monomer is a mixture of two or more ofthese compounds.

The anion associated with the ammonium functionality of the cationicmonomer is not particularly limited, and many anions are useful inconnection with various embodiments of the invention. In someembodiments, the anion is a halide anion, such as chloride, bromide,fluoride, or iodide; in some such embodiments, the anion is chloride. Inother embodiments the anion is BF₄, N(SO₂CF₃)₂, O₃SCF₃, or O₃SC₄F₉. Inother embodiments, the anion is methyl sulfate. In still otherembodiments, the anion is hydroxide. In some embodiments, the one ormore cationic monomers includes a mixture of two or more of theseanions. In some embodiments, polymerization is carried out using2-(dimethylamino)ethyl acrylate or 2-(dimethylamino)ethyl methacrylate,and the corresponding ammonium functionality is formed in situ byreacting the amino groups present within the polymer with a suitablealkyl halide to form the corresponding ammonium halide functionality. Inother embodiments, the ammonium functional monomer is incorporated intothe cationic polymer and then the anion is exchanged to provide adifferent anion. In such embodiments, ion exchange is carried out usingany of the conventional processes known to and commonly employed bythose having skill in the art.

In embodiments, the polymerized product of the cationic monomer ispresent in the cationic polymer at about 2 wt % to 45 wt % based on thetotal weight of the cationic polymer, or at about 2 wt % to 35 wt % ofthe cationic polymer, or at about 4 wt % to 25 wt % of the cationicpolymer, or at about 6 wt % to 15 wt % of the cationic polymer, or atabout 7 wt % to 10 wt % of the cationic polymer, or in variousintermediate levels such as 3 wt %, 5 wt %, 6 wt %, 8 wt %, and allother such individual values represented by 1 wt % increments between 2and 45 wt %, and in any range spanning these individual values in 1 wt %increments, such as 2 wt % to 4 wt %, 7 wt % to 38 wt %, 20 wt % to 25wt %, and the like.

In embodiments, the polymerized product of one or more additionalmonomers is included in the cationic polymers of the invention. Suchadditional monomers are not particularly limited by structure, butexclude monomers having anionic functionality. Non-limiting examples ofadditional monomers are

N-vinyl pyrrolidone, isobutyl (meth)acrylate, n-butyl (meth)acrylate,isopropyl (meth)acrylate, n-propyl (meth)acrylate, methyl(meth)acrylate, ethyl (meth)acrylate, vinyl acetate, hydroxyethyl(meth)acrylate, hydroxypropyl (meth)acrylate, octadecyl (meth)acrylate,stearyl (meth)acrylate, dimethyl acrylamide,N-(hydroxymethyl)-acrylamide, dimethylaminoethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, polydimethylsiloxane(meth)acrylate), KF 2001(mercapto modified dimethylsiloxane),perfluorobutyl sulfonamido n-methyl ethyl acrylate, andhexafluoropropylene oxide oligomer amidol (meth)acrylate. In someembodiments, the additional monomer is a mixture of two or more of thesemonomers. In some embodiments, the additional monomer is vinyl acetate.In some embodiments, the additional monomer is isobutyl acrylate. Insome embodiments, the additional monomer is N-vinyl pyrrolidone. In someembodiments, the additional monomer is a mixture of vinyl acetate andN-vinyl pyrrolidone.

In some embodiments, the additional monomer is selected to impart to theresulting cationic polymer a reduced level of measurable adhesion to aselected substrate, while still providing the level of tack of thecationic polymer relative to the polymer without the one or moreadditional monomers. In other embodiments, the additional monomer isselected to impart to the resulting cationic polymer a reduced level oftack, while maintaining a substantially constant level of adhesion ofthe cationic polymer to a selected substrate relative to the polymerwithout the one or more additional monomers. In still other embodiments,the additional monomer is selected to impart to the resulting cationicpolymer an increased level of tack, while maintaining a substantiallyconstant level of adhesion of the cationic polymer to a selectedsubstrate relative to the polymer without the one or more additionalmonomers.

The polymerized product of the one or more additional monomers ispresent in the cationic polymer at about 0 wt % to 30 wt % based on thetotal weight of the cationic polymer, or about 2 wt % to 20 wt % basedon the total weight of the cationic polymer, or at about 3 wt % to 15 wt% of the cationic polymer, or at about 5 wt % to 10 wt % of the cationicpolymer, or in various intermediate levels such as 1 wt %, 3 wt %, 4 wt%, 5 wt %, 6 wt %, 7 wt %, and all other such individual valuesrepresented by 1 wt % increments between 0 wt % and 30 wt %, and in anyrange spanning these individual values in 1 wt % increments, such asabout 2 wt % to 4 wt %, about 11 wt % to 28 wt %, about 7 wt % to 17 wt%, and the like. All such ranges suitably include 0%.

In some embodiments, the additional monomer has two or morepolymerizable functionalities; such monomers are referred to ascrosslinkers. Crosslinkers that are useful in forming the cationicpolymers include, without limitation, diacrylates such as ethyleneglycol diacrylate, hexanediol diacrylate, and tripropyleneglycoldiacrylate; triacrylates such as glycerol triacrylate andtrimethylolpropane triacrylate; and tetraacrylates such as erythritoltetraacrylate and pentaerythritol tetraacrylate; divinyl benzene andderivatives thereof, and the like. In some embodiments, the crosslinkeris a photoactive crosslinker. Photoactive crosslinkers include, forexample, benzaldehyde, acetaldehyde, anthraquinone, substitutedanthraquinones, various benzophenone-type compounds and certainchromophore-substituted vinylhalomethyl-s-triazines, such as2,4-bis(trichloromethyl)-6-p-methoxystyryl-s-triazine. In someembodiments the polymerized product of the crosslinker, as an additionalmonomer, is present in amounts as high as 30 wt % based on the totalweight of the polymer, in other embodiments the polymerized product ofthe crosslinker is present in the cationic polymer at about 0 wt % to 10wt % based on the total weight of the polymer, for example at about 0.01wt % to 5 wt % or about 0.1 wt % to 2 wt %.

The zwitterionic polymers of the invention are copolymers that includethe polymerized product of an anionic monomer that is acrylic acid,methacrylic acid, a salt thereof, or a blend thereof; an acrylate ormethacrylate ester of an alcohol having between 8 and 12 carbons; and acationic monomer that is an acrylate or methacrylate ester havingalkylammonium functionality. Optionally, one or more additional monomersare included in the zwitterionic polymers of the invention. In someembodiments the anionic monomer is acrylic or methacrylic acid, the acidis converted either before or after polymerization to a correspondingcarboxylate salt by neutralization. In some embodiments, the acrylicacid, methacrylic acid, or a salt thereof is a mixture of two or morethereof. In some embodiments, the acrylate or methacrylate ester is amixture of two or more such esters; in some embodiments, the cationicmonomer is a mixture of two or more such cationic monomers.

In embodiments, the polymerized product of acrylic acid, methacrylicacid, a salt thereof or blend thereof is present in the zwitterionicpolymer at about 0.2 wt % to 5 wt % based on the total weight of thepolymer, or at about 0.5 wt % to 5 wt % of the zwitterionic polymer, orin various intermediate levels such as 0.3 wt %, 0.4 wt %, 0.6 wt %, 0.7wt %, and all other such individual values represented by 0.1 wt %increments between 0.2 and 5.0 wt %, and in ranges spanning between anyof these individual values in 0.1 wt % increments, such as 0.2 wt % to0.9 wt %, 1.2 wt % to 3.1 wt %, and the like.

In embodiments, the acrylate or methacrylate ester of an alcohol havingbetween 8 and 12 carbons includes acrylate or methacrylate esters oflinear, branched, or cyclic alcohols. While not intended to be limiting,examples of alcohols useful in the acrylate or methacrylate estersinclude octyl, isooctyl, nonyl, isononyl, decyl, undecyl, and dodecylalcohol. In embodiments, the alcohol is isooctyl alcohol. In someembodiments, the acrylate or methacrylate ester of an alcohol havingbetween 8 and 12 carbons is a mixture of two or more such compounds. Inembodiments, polymerized product of the acrylate or methacrylate esterof an alcohol having between 8 and 12 carbons is present in thezwitterionic polymer at about 50 wt % to 95 wt % of the total weight ofthe polymer, or at about 60 wt % to 90 wt % of the total weight of thepolymer, or at about 75 wt % to 85 wt % of the total weight of thepolymer, or in various intermediate levels such as 51 wt %, 52 wt %, 53wt %, 54 wt %, and all other such values individually represented by 1wt % increments between 50 wt % and 95 wt %, and in any range spanningbetween any of these individual values in 1 wt % increments, for exampleranges such as about 54 wt % to 81 wt %, about 66 wt % to 82 wt %, about77 wt % to 79 wt %, and the like.

In embodiments, the cationic monomer is an acrylate or methacrylateester including an alkylammonium functionality. In some embodiments, thecationic monomer is a 2-(trialkyl ammonium)ethyl acrylate or a2-(trialkylammonium)ethyl methacrylate. In such embodiments, the natureof the alkyl groups is not particularly limited; however, cost andpracticality limit the number of useful embodiments. In embodiments, the2-(trialkyl ammonium)ethyl acrylate or 2-(trialkylammonium)ethylmethacrylate is formed by the reaction of 2-(dimethylamino)ethylacrylate or 2-(dimethylamino)ethyl methacrylate with an alkyl halide; insuch embodiments, at least two of the three alkyl groups of the2-(trialkyl ammonium)ethyl acrylate or 2-(trialkylammonium)ethylmethacrylate are methyl. In some such embodiments, all three alkylgroups are methyl groups. In other embodiments, two of the three alkylgroups are methyl and the third is a linear, branched, cyclic, oralicyclic group having between 2 and 24 carbon atoms, or between 6 and20 carbon atoms, or between 8 and 18 carbon atoms, or 16 carbon atoms.In some embodiments, the cationic monomer is a mixture of two or more ofthese compounds.

The anion associated with the ammonium functionality of the cationicmonomer is not particularly limited, and many anions are useful inconnection with various embodiments of the invention.

In some embodiments, the anion is a halide anion, such as chloride,bromide, fluoride, or iodide; in some such embodiments, the anion ischloride. In other embodiments the anion is BF₄, N(SO₂CF₃)₂, O₃SCF₃, orO₀₃SC₄F₉. In other embodiments, the anion is methyl sulfate. In stillother embodiments, the anion is hydroxide. In some embodiments, the oneor more cationic monomers includes a mixture of two or more of theseanions. In some embodiments, polymerization is carried out using2-(dimethylamino)ethyl acrylate or 2-(dimethylamino)ethyl methacrylate,and the corresponding ammonium functionality is formed in situ byreacting the amino groups present within the polymer with a suitablealkyl halide to form the corresponding ammonium halide functionality. Inother embodiments, the ammonium functional monomer is incorporated intothe cationic polymer and then the anion is exchanged to provide adifferent anion. In such embodiments, ion exchange is carried out usingany of the conventional processes known to and commonly employed bythose having skill in the art.

In embodiments, the polymerized product of the cationic monomer ispresent in the zwitterionic polymer at about 2 wt % to 45 wt % based onthe total weight of the zwitterionic polymer, or at about 2 wt % to 35wt % of the zwitterionic polymer, or at about 4 wt % to 25 wt % of thezwitterionic polymer, or at about 6 wt % to 15 wt % of the zwitterionicpolymer, or at about 7 wt % to 10 wt % of the zwitterionic polymer, orin various intermediate levels such as 3 wt %, 5 wt %, 6 wt %, 8 wt %,and all other such individual values represented by 1 wt % incrementsbetween 2 and 45 wt %, and in any range spanning these individual valuesin 1 wt % increments, such as 2 wt % to 4 wt %, 7 wt % to 38 wt %, 20 wt% to 25 wt %, and the like.

In embodiments, the polymerized product of one or more additionalmonomers is included in the cationic polymers of the invention. Suchadditional monomers are not particularly limited by structure andinclude, in some embodiments, anionic functional monomers. Non-limitingexamples of additional monomers are isobutyl acrylate, isobutylmethacrylate, n-butyl acrylate, n-butyl methacrylate, isopropylacrylate, isopropyl methacrylate, n-propyl acrylate, n-propylmethacrylate, methyl acrylate, methyl methacrylate, ethyl acrylate,ethyl methacrylate, vinyl acetate, N-vinyl pyrrolidone, hydroxyethylacrylate, or hydroxyethyl methacrylate. In some embodiments, theadditional monomer is a mixture of two or more of these monomers. Insome such embodiments, the additional monomer is vinyl acetate. In somesuch embodiments, the additional monomer is N-vinyl pyrrolidone. In someembodiments the additional monomer is isobutyl acrylate. In someembodiments, the additional monomer is a mixture of vinyl acetate andN-vinyl pyrrolidone. In some embodiments, the additional monomer is amixture of vinyl acetate and isobutyl acrylate. In some embodiments, theadditional monomer is a mixture of isobutyl acrylate and N-vinylpyrrolidone.

The polymerized product of the one or more additional monomers ispresent in the zwitterionic polymer at about 0 wt % to 30 wt % based onthe total weight of the zwitterionic polymer, or about 2 wt % to 20 wt %based on the total weight of the zwitterionic polymer, or at about 3 wt% to 15 wt % of the zwitterionic polymer, or at about 5 wt % to 10 wt %of the zwitterionic polymer, or in various intermediate levels such as 1wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, and all other suchindividual values represented by 1 wt % increments between 0 wt % and 30wt %, and in any range spanning these individual values in 1 wt %increments, such as about 2 wt % to 4 wt %, about 11 wt % to 28 wt %,about 7 wt % to 17 wt %, and the like. All such ranges suitably include0%.

In some embodiments, the additional monomer is selected to impart to theresulting zwitterionic polymer a reduced level of measurable adhesion toa selected substrate, while still providing the level of tack of thezwitterionic polymer relative to the polymer without the one or moreadditional monomers. In other embodiments, the additional monomer isselected to impart to the resulting zwitterionic polymer a reduced levelof tack, while maintaining a substantially constant level of adhesion ofthe zwitterionic polymer to a selected substrate relative to the polymerwithout the one or more additional monomers. In still other embodiments,the additional monomer is selected to impart to the resultingzwitterionic polymer an increased level of tack, while maintaining asubstantially constant level of adhesion of the zwitterionic polymer toa selected substrate relative to the polymer without the one or moreadditional monomers.

In some embodiments, the additional monomer has two or morepolymerizable functionalities; such monomers are referred to ascrosslinkers. Crosslinkers that are useful in forming the zwitterionicpolymers include, without limitation, diacrylates such as ethyleneglycol diacrylate, hexanediol diacrylate, and tripropyleneglycoldiacrylate; triacrylates such as glycerol triacrylate andtrimethylolpropane triacrylate; and tetraacrylates such as erythritoltetraacrylate and pentaerythritol tetraacrylate; divinyl benzene andderivatives thereof, and the like. In some embodiments, the crosslinkeris a photoactive crosslinker. Photoactive crosslinkers include, forexample, benzaldehyde, acetaldehyde, anthraquinone, substitutedanthraquinones, various benzophenone-type compounds and certainchromophore-substituted vinylhalomethyl-s-triazines, such as2,4-bis(trichloromethyl)-6-p-methoxystyryl-s-triazine. In someembodiments the polymerized product of the crosslinker, as an additionalmonomer, is present in amounts as high as 30 wt % based on the totalweight of the zwitterionic polymer, in other embodiments the polymerizedproduct of the crosslinker is present in the zwitterionic polymer atabout 0 wt % to 10 wt % based on the total weight of the polymer, forexample at about 0.01 wt % to 5 wt % or about 0.1 wt % to 2 wt %.

Polymerization Processes

The polymerization of the cationic and zwitterionic polymers are carriedout using conventional thermal or radiation polymerization techniquesfamiliar to those of skill. For example, in some embodiments, themonomers and optional crosslinker are admixed, coated onto a tapebacking or other support, and irradiated by UV or ebeam radiation. Insome embodiments, air is partially excluded or limited in the reactionarea during the irradiation. In some embodiments, an emulsion of monomeris formed and polymerization is carried out using UV or thermalinitiation of the polymerization reaction. The emulsion is awater-in-oil or oil-in-water emulsion. In some embodiments, a solutionof the monomers is formed in a solvent that is water, an aqueousmixture, or in a solvent other than water, and polymerization is carriedout using UV or thermal initiation similarly to the emulsion reaction.

In some embodiments where UV radiation is employed, a photoinitiator isemployed to initiate the polymerization reaction via photolysis. In somesuch embodiments, a photoinitiator is selected based on the wavelengthof UV radiation to be employed. Where a photoinitiator is employed, itis included in the polymerization mixture at about 0.01 wt % to 5 wt %based on the total weight of the monomers, for example about 0.1 wt % to2 wt % based on the total weight of the monomers, or about 0.2 wt % to 1wt % based on the total weight of the monomers. Non-limiting examples ofsuitable photoinitiators include any of the metal iodides, alkyl metalcompounds, or azo compounds familiar to those having skill in the art ofUV initiated polymerization; and those sold under the trade nameIRGACURE® by Ciba Specialty Chemicals Corp. of Tarrytown, N.Y.; thosesold under the trade name CHEMCURE® by Sun Chemical Company of Tokyo,Japan; and those sold under the trade name LUCIRIN® by BASF Corporationof Charlotte, N.C. In the case of emulsion polymerization, water solubleinitiators are preferred.

In some embodiments where thermal decomposition is employed to initiatepolymerization, emulsion polymerization of the monomers employed to makethe cationic or zwitterionic polymers of the invention is carried out byblending the monomers, surfactant(s), and a thermal initiator in water,followed by heating the emulsion to a temperature wherein decompositionof the initiator occurs at a rate suitable to sustain a suitable rate ofpolymerization. Non-limiting examples of suitable thermal initiatorsinclude any of the organic peroxides or azo compounds conventionallyemployed by those skilled in the art of thermal initiation ofpolymerization, such a dicumyl peroxide, benzoyl peroxide, orazobisbutyrylnitrile (AIBN), and thermal initiators sold under the tradename VAZO® by duPont deNemours and Company of Wilmington, Del. In thecase of emulsion polymerization, water soluble initiators are preferred.

In some embodiments, the monomers and optional crosslinker are admixed,coated onto a tape backing or other support, and irradiated or heated toinitiate polymerization. In some such embodiments, air is partiallyexcluded or limited in the reaction area during the polymerization. Insome such embodiments, UV or thermal polymerization is subjected toprepolymerization prior to coating onto the support and completingpolymerization and/or crosslinking. Prepolymerization is a bulk orcontinuous polymerization method wherein a minor amount ofpolymerization, for example 1% to 10%, of the bulk coating compositionis carried out to achieve a target viscosity. The prepolymers are of anysuitable molecular weight and are soluble in the monomer mixture used toform the cationic or zwitterionic polymer. Prepolymers are formed insitu or added to a reaction vessel at any amount that is useful toprovide the target coating viscosity. In a typical prepolymerization, amonomer mixture is subjected to UV or thermal radiation in bulk orcontinuous mode until the desired viscosity is reached, forming aprepolymerized mixture. In some embodiments, targeted viscosities forthe prepolymerized coatings are from about 10 cP to 2000 cP, or about100 cP to 1000 cP. In embodiments, one or more additional monomers,crosslinkers, initiators, or a combination thereof are then added to theprepolymerized mixture. In some embodiments, the one or more additionalmonomers, crosslinkers, initiators, or combination thereof include someor all of the same compounds, present in the same ratios, as those addedto the mixture that is prepolymerized. The prepolymerized mixture isthen coated onto the support and cured, wherein the viscosity of theprepolymerized mixture allows a thicker layer to be coated than would bepracticable by coating without prepolymerization.

In other embodiments, an emulsion of monomer is formed andpolymerization is carried out using UV or thermal initiation of thepolymerization reaction. The emulsion is a water-in-oil or anoil-in-water emulsion. In some such embodiments, the emulsion is anoil-in-water emulsion, wherein the one or more monomers are stabilizedin a bulk water phase by employing one or more surfactants. In variousembodiments, the surfactant is cationic, anionic, zwitterionic, ornonionic in nature and is the structure thereof not otherwiseparticularly limited. In some embodiments, the surfactant is also amonomer and becomes incorporated within the cationic or zwitterionicpolymer molecules. In other embodiments, the surfactant is present inthe polymerization reaction vessel but is not incorporated into thecationic or zwitterionic polymer as a result of the polymerizationreaction.

Non-limiting examples of anionic surfactants useful in formingoil-in-water emulsions of the monomers employed to form the cationic orzwitterionic polymers include ammonium, sodium, lithium, or potassiumsalts of lauryl sulfonic acid, dioctyl sodium sulfosuccinic acid,ammonium, sodium, lithium, or potassium salts of perfluorobutanesulfonicacid, ammonium, sodium, lithium, or potassium salts ofperfluorooctanesulfonic acid, ammonium, sodium, lithium, or potassiumsalts of perfluorooctanoic acid, sodium dodecyl sulfate, sodiumdodecylbenzenesulfonate, sodium laureth sulfate, sodium lauroylsarcosinate, sodium myreth sulfate, sodium pareth sulfate, ammonium,sodium, lithium, or potassium salts of stearic acid, and combinations ofone or more thereof.

Non-limiting examples of nonionic surfactants useful in formingoil-in-water emulsions of the monomers employed to form the cationic orzwitterionic polymers include block copolymers of ethylene oxide andpropylene oxide, such as those sold under the trade names PLURONIC®,KOLLIPHOR®, or TETRONIC®, by the BASF Corporation of Charlotte, N.C.;ethoxylates formed by the reaction of ethylene oxide with a fattyalcohol, nonylphenol, dodecyl alcohol, and the like, including thosesold under the trade name TRITON®, by the Dow Chemical Company ofMidland, Mich.; oleyl alcohol; sorbitan esters; alkylpolyglycosides suchas decyl glucoside; sorbitan tristearate; and combinations of one ormore thereof.

Non-limiting examples of cationic surfactants useful in formingoil-in-water emulsions of the monomers employed to form the cationic orzwitterionic polymers include benzalkonium chloride, cetrimoniumbromide, demethyldioctadecylammonium chloride, lauryl methyl gluceth-10hydroxypropyl diammonium chloride, tetramethylammonium hydroxide,monoalkyltrimethylammonium chlorides, monoalkyldimethylbenzylammoniumchlorides, dialkylethylmethylammonium ethosulfates,trialkylmethylammonium chlorides, polyoxyethylenemonoalkylmethylammoniumchlorides, and diquaternaryammonium chlorides; the ammonium functionalsurfactants sold by Akzo Nobel N.V. of Amsterdam, the Netherlands, underthe trade names ETHOQUAD®, ARQUAD®, and DUOQUAD®; and mixtures thereof.Of particular use in forming oil-in-water emulsions for polymerizationof the zwitterionic polymers of the invention are the ETHOQUAD®surfactants, for example, ETHOQUAD® C/12, C./25, C./12-75, and the like.In some embodiments, ETHOQUAD® C./25 is usefully employed to make highsolids emulsions in water of the monomers employed to make thezwitterionic polymers of the invention.

Where a cationic surfactant is employed in an oil-in-water emulsionpolymerization reaction, it is employed in an amount of about 1.0 wt %to 6.0 wt % based on the total weight of the monomers, or at about 2.0wt % to 4.0 wt % of the monomers, or in various intermediate levels suchas 1.1 wt %, 1.2 wt %, 1.3 wt %, 1.4 wt %, 1.5 wt %, 1.6 wt %, 1.7 wt %,1.8 wt %, 1.9 wt %, 2.1 wt %, 2.2 wt %, and all other such individualvalues represented by 0.1 wt % increments between 1.0 and 6.0 wt %, andin any range spanning these individual values in 0.1 wt % increments,such as 2.3 wt % to 4.6 wt %, 4.5 wt % to 4.7 wt %, and the like.

Non-limiting examples of zwitterionic surfactants useful in formingoil-in-water emulsions of the monomers employed to form the cationic orzwitterionic polymers include betaines and sultaines, such ascocamidopropyl betaine, hydroxysultaine, and cocamidopropylhydroxysultaine; others include lecithin, 3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), and sodium2-[1-(2-hydroxyethyl)-2-undecyl-4,5 -dihydroimidazol-1-ium-1-yl]acetate(sodium lauroamphacetate). Where a zwitterionic surfactant is employedin an oil-in-water emulsion polymerization reaction, it is employed inan amount of about 1.0 wt % to 10.0 wt % based on the total weight ofthe monomers, or at about 2.0 wt % to 6.0 wt % of the monomers, or invarious intermediate levels such as 1.1 wt %, 1.2 wt %, 1.3 wt %, 1.4 wt%, 1.5 wt %, 1.6 wt %, 1.7 wt %, 1.8 wt %, 1.9 wt %, 2.1 wt %, 2.2 wt %,and all other such individual values represented by 0.1 wt % incrementsbetween 1.0 and 10.0 wt %, and in any range spanning these individualvalues in 0.1 wt % increments, such as 2.3 wt % to 4.6 wt %, 4.5 wt % to4.7 wt %, and the like.

In some embodiments, emulsion polymerization of the monomers employed tomake the cationic or zwitterionic polymers of the invention is carriedout by blending the monomers, surfactant(s), and a UV initiator inwater, followed by irradiating with UV radiation at a wavelengthcorresponding to the preferred decomposition wavelength of the selectedinitiator for a period of time. In other embodiments, emulsionpolymerization of the monomers employed to make the cationic orzwitterionic polymers of the invention is carried out by blending themonomers, surfactant(s), and a thermal initiator in water, followed byheating the emulsion to a temperature where decomposition of the thermalinitiator is induced at a suitable rate. In some embodiments wheremethacrylic acid or acrylic acid are employed in the monomer mixture,sodium, lithium, ammonium, or potassium hydroxide is added to themonomer mixture to neutralize the acid functionality and form thecorresponding salt. In other embodiments, such neutralization is carriedout after completion of the polymerization reaction. Neutralization, inembodiments, means adjusting the pH of the water phase from betweenabout 2 and 3 to between about 4 and 7, for example between about 5 and6.

In some embodiments, ETHOQUAD® C./25 is usefully employed to make highsolids emulsions of the monomers. In this context, “solids” are definedas all ingredients of the emulsion other than water. High solidsemulsions are formed, for example, at about 15 wt % and 60 wt % totalsolids in water, or about 25 wt % to 60 wt % total solids in water, orabout 30 wt % to 50 wt % solids in water, or in various intermediatelevels such as 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, 22wt %, 23 wt %, 24 wt %, 26 wt %, 27 wt %, and all other such individualvalues represented by 1 wt % increments between 15 wt % and 60 wt %solids in water, and in any range spanning these individual values in 1wt % increments, such as 23 wt % to 46 wt %, 45 wt % to 57 wt %, and thelike.

In general, conditions of emulsion polymerization and methodologyemployed are the same or similar to those employed in conventionalemulsion polymerization methods. In some embodiments, the oil-in-wateremulsion polymerization is carried out using thermal initiation. In suchembodiments, one useful polymerization initiator is V-50 (obtained fromWako Pure Chemical Industries Ltd. of Osaka, Japan). In some suchembodiments, the temperature of the emulsion is adjusted prior to andduring the polymerization to about 30° C. to 100° C., for example toabout 40° C. to 80° C., or about 40° C. to 60° C., or about 45° C. to55° C. Agitation of the emulsion at elevated temperature is carried outfor a suitable amount of time to decompose substantially all of thethermal initiator, and react substantially all of the monomers added tothe emulsion to form a polymerized emulsion. In some embodiments,elevated temperature is maintained for a period of about 2 hours to 24hours, or about 4 hours to 18 hours, or about 8 hours to 16 hours.During polymerization, it is necessary in some embodiments to addadditional thermal initiator to complete the reaction of substantiallyall of the monomer content added to the reaction vessel. It will beappreciated that completion of the polymerization is achieved by carefuladjustment of conditions, and standard analytical techniques, such asgas chromatographic analysis of residual monomer content, will informthe skilled artisan regarding the completion of polymerization.

In other embodiments, the polymerization is a solvent polymerization,wherein the monomers form a solution in a solvent or mixture of two ormore solvents. The solvents include water but in some embodiments anon-aqueous solvent or solvent mixture is employed. Examples of suitablesolvents and solvent mixtures include, in various embodiments, one ormore of ethanol, methanol, toluene, methyl ethyl ketone, ethyl acetate,isopropyl alcohol, tetrahydrofuran, 1-methyl-2-pyrrolidinone,2-butanone, acetonitrile, dimethylformamide, dimethyl sulfoxide,dimethylacetamide, dichloromethane, t-butanol, methyl isobutyl ketone,methyl t-butyl ether, and ethylene glycol. In general, conditions ofsolvent polymerization and methodology employed are the same or similarto those employed in conventional solvent polymerization methods. Insome embodiments, the solvent polymerization is carried out usingthermal initiation. In such embodiments, one useful polymerizationinitiator is VAZO® 67. In some such embodiments, the temperature of themonomer solution is adjusted prior to and during the polymerization toabout 30° C. to 150° C., for example to about 50° C. to 1300° C., orabout 60° C. to 120° C., or about 60° C. to 100° C. Agitation of thesolution at elevated temperature is carried out for a suitable amount oftime to decompose substantially all of the thermal initiator, and reactsubstantially all of the monomers to form a polymer solution. In someembodiments, elevated temperature is maintained for a period of about 2hours to 24 hours, or about 4 hours to 18 hours, or about 8 hours to 16hours. During polymerization, it is necessary in some embodiments to addadditional thermal initiator to complete the reaction of substantiallyall of the monomer content added to the reaction vessel. It will beappreciated that completion of the polymerization is achieved by carefuladjustment of conditions, and standard analytical techniques such as gaschromatographic analysis of residual monomer content will inform theskilled artisan regarding the completion of polymerization.

In some embodiments, the solvent polymerization as described above is aUV polymerization; that is, a UV initiator is employed instead of athermal initiator and the polymerization is carried out substantially asdescribed for the solvent polymerization except that the solution isirradiated with UV radiation at a wavelength corresponding to thepreferred decomposition wavelength of the selected initiator for aperiod of time. In some embodiments, solution UV polymerization iscarried out without adding heat to the solution. In other embodiments,heat is further added to the solution, for example to facilitate mixingas viscosity of the solution increases during the polymerizationprocess.

Adhesive Compositions and Coating

The adhesive compositions of the invention include at least one cationicpolymer or zwitterionic polymer, and optionally one or more additionalcomponents. Additional components include one or more adhesionpromoters, tackifying agents, surfactants, antifouling agents, thermalor oxidative stabilizers, colorants, adjuvants, plasticizers, solvents,crosslinkers, or mixtures thereof.

In some embodiments, the cationic or zwitterionic polymer isprecipitated from a polymerization emulsion mixture or otherwisepurified to remove one or more of residual monomer, unreacted initiator,low molecular weight products, and surfactant, and the purified cationicor zwitterionic polymer is the adhesive composition. In otherembodiments, the polymer is further compounded with one or moreadditional components, described below, to form the adhesivecomposition. The adhesive composition is then employed in an extrusioncoating or dissolved in water or another solvent and solvent coated on asupport to form a masking article as will be described below. In otherembodiments, the emulsion is simply dried to form the adhesivecomposition, and the dried composition is extrusion coated or dissolvedin a solvent other than water and coated onto a support; in someembodiments, one or more additional components are added viaconventional compounding or addition processes to form the adhesivecomposition. Extrusion and solvent coatings are carried out usingconventional methods such as those employed by the skilled artisan.Non-limiting examples of solvent coating processes useful in conjunctionwith the adhesive compositions of the invention include knife coating,slot coating, die coating, flood coating, rod coating, curtain coating,cast coating, spray coating, brush coating, dip coating, kiss coating,gravure coating, pattern coating processes such as stripe coating, printcoating operations such as flexographic, inkjet, or screen printcoating, and the like. Solvent coating is followed by drying using asuitable temperature and period of time for drying that is sufficient toremove a substantial portion of the solvent and any other volatilesubstances associated with the adhesive composition.

In some embodiments, an emulsified cationic or zwitterionic polymer, atthe end of an emulsion polymerization process, is employed as theadhesive composition and is coated as-is onto one or more supports toform a masking article. In such embodiments, water and one or moresurfactants employed in the polymerization will remain associated withthe adhesive composition, along with any residual unreacted monomers orinitiators. The adhesive composition is coated and dried for a period oftime sufficient to remove a substantial portion of the water, but inmost embodiments the surfactant(s) employed will remain in the driedcoating whether or not such surfactants are reacted with and become partof the polymer. Drying of the emulsion will, in some embodiments, alsoresult in removal of some portion or a substantial portion of anyunreacted volatile monomers. In some embodiments, one or more additionalcomponents are added to the emulsion containing the cationic orzwitterionic polymer to form the adhesive composition, and the amendedemulsion is employed to coat one or more supports and dried to remove asubstantial portion of the water and some or a substantial portion ofany other remaining volatile components. After drying, it is desirablethat the emulsified adhesive compositions include no more than 1 wt %,for example between 0.5 wt % and 5 ppm, or between about 500 ppm and 10ppm, or between about 100 ppm and 1 ppm of unreacted monomers, based onthe total weight of monomers added to the emulsion polymerizationreaction vessel.

Cationically emulsified adhesive compositions of the invention arecharacterized by excellent coating viscosity and high shear stability.In embodiments, the viscosity of a cationically stabilized adhesivecomposition of the invention is between about 20 cP and 2500 cP, orabout 100 cP and 1500 cP, or about 400 cP to 1000 cP. The emulsionviscosity is determined in part by the solids content of the emulsionand the molecular weight of the cationic or zwitterionic polymer formed.The emulsions are stable under shear stress, such that onset of shearinstability occurs at or above at least about 80 Pa, for example betweenabout 90 Pa and 300 Pa, or about 100 Pa and 200 Pa. The viscosity andshear stability of the cationically emulsified adhesive compositions ofthe invention provide broad flexibility in selecting coating methods forcoating the adhesive compositions onto one or more supports to form amasking article. Non-limiting examples of useful coating processesemployed in conjunction with the cationally emulsified adhesivecompositions include knife coating, slot coating, die coating, floodcoating, rod coating, curtain coating, spray coating, brush coating, dipcoating, kiss coating, gravure coating, print coating operations such asflexographic, inkjet, or screen print coating, and the like. In someembodiments the adhesive compositions are coated as a continuouscoating; in other embodiments they are pattern coated as described inU.S. Pat. Nos. 4,798,201 and 5,290,615 or using another technique.

Coating of the emulsified adhesive compositions is followed by dryingusing a suitable temperature and period of time for drying that issufficient to remove a substantial portion of the water and any othervolatile substances associated with the emulsion mixture.

Adhesive Articles

The adhesive articles of the invention include at least an adhesivecomposition of the invention and a support. Coating of the adhesivecompositions onto one or more supports is generally described above. Itis an advantage of the invention that adhesive articles of the inventionare easy to make, in many embodiments employing a single pass coatingoperation to fabricate an adhesive article. In embodiments where theadhesive composition is coated as an emulsion or from a solvent, thesingle coating pass is followed by a drying step. No additional stepsare required in order to fabricate an adhesive article of the invention.Most significantly, the adhesive articles of the invention arecharacterized by the absence of an edge treatment; the adhesive articleshave a constant composition over the entirety of the coated support.However, performance of the adhesive articles in masking applications iscommensurate with or superior to that of conventional edge treatedmasking articles.

While the adhesive articles of the invention are not particularlylimited as to type and shape of the support, in many embodiments thesupport is a sheet or film suitable for converting to a tape article.Tape articles are rectangular strips that typically are converted fromlarger sheets into the desired width and length. Such conversion istypically carried out after coating the adhesive compositions onto thetape film or sheet. Thus, when the masking article is to be a tapearticle, critical variables in the adhesive coating process are film orsheet thickness of the support and chemical composition of the supportin conjunction with the nature of the adhesive composition to be coated,including whether the coating is an emulsion coating, solvent bornecoating, extrusion coating, or UV curable monomeric or prepolymerizedcoating.

It is an advantage of the invention that the adhesive articles of theinvention are masking articles, whether or not they are used as such. Inorder to be used as a masking article, any of the adhesive articlesdescribed herein are useful as such with no further modification.

In some embodiments, the adhesive article is not a tape. An adhesivearticle is employed in any form or shape, including non-rectilinearshapes and irregular shapes. In other embodiments, the adhesive articleis a tape article. Supports employed in forming tape articles of theinvention are between about 12 μm and 3 cm thick, for example about 25μm to 200 μm or 75 μm to 150 μm thick for a “standard” dimension tapearticle, and between 200 μm and 3 cm for specialized tape articles.Specialized tape articles include articles including a foamed support,for example.

Chemical composition of suitable tape supports include those selectedfrom a wide variety of polymers and blends thereof. Non-limitingexamples of suitable tape supports include paper, including both flat orsmooth paper as well as textured paper such as crepe paper, natural orsynthetic polymer films, nonwovens made from natural and/or syntheticfibers and combinations thereof, fabric reinforced polymer films, fiberor yarn reinforced polymer films or nonwovens, and multiple layerlaminated constructions. Examples of suitable synthetic polymer filmsinclude those made from polyolefins such as polyethylene orpolypropylene, polyvinyl chloride, polytetrafluoroethylene andcopolymers thereof with fluorinated and non-fluorinated monomers,polyvinylidene chloride and copolymers thereof, polyvinylidene fluorideand copolymers thereof, polyamides such as nylon 6, nylon 6,6, and nylon12, polyesters such as polyethylene terephthalate, polylactic acid, andpolyethylene naphthalate, polyimides, polyurethanes, polyacrylic esters,polycarbonates, and the like, and blends of two or more such materials.Such support materials include, in some embodiments, additionalmaterials such as fillers, stabilizers, colorants, and the like. Metalsupports, such as tin or aluminum film or sheet supports, are alsouseful in some embodiments. In some embodiments the polymers forming thesupport are in the form of a foam support. In some embodiments thesupport is a metalized film. In some embodiments the support is amultilayered support having two or more layers; in some such embodimentsthe layers are laminated. Combinations of two or more such compositionsand constructions are also useful in various embodiments of theinvention.

In some embodiments the support is embossed or microembossed; embossedor microembossed supports include any of the support materials andconstructions described above. In some such embodiments, embossed ormicroembossed features are disposed on the major side of the supportcontacting the adhesive composition. In other embodiments the embossedor microembossed features are disposed on the major side of the supportopposite to the side coated with the adhesive composition. In stillother embodiments embossed or microembossed features are disposed onboth major sides of the support; the features disposed on the two majorsides are the same or different in various embodiments. In someembodiments, the adhesive composition itself includes embossed features,either by virtue of being coated on an embossed surface, or by disposingan adhesive composition between the support and an embossed releaseliner. Embossed features imparted to the adhesive compositionsthemselves are useful, for example, to impart repositionability to themasking articles of the invention or allow for air bleed from betweenthe adhesive article and the masked surface. Embossing andmicroembossing are accomplished using techniques known to the skilledartisan and include nip roll embossing using a patterned nip roll, andprofile extrusion; secondary processes such as tentering and slicing arefurther employed in some embodiments to modify surface structuresimparted by the embossing or microembossing process.

The materials that constitute the support are not particularly limited,and the same materials useful as tape supports are similarly useful inthe form of supports other than films or sheets. In various embodiments,such supports are usefully combined with the adhesive compositions ofthe invention to make adhesive articles other than tapes. In some suchembodiments the adhesive articles are masking articles. In otherembodiments, the adhesive articles are not used in a maskingapplication. Adhesive articles usefully formed by coating with theadhesive compositions of the invention include, for example, roofingshingles, carpet squares, carpet backings, vinyl flooring squares,adhesive wall tiles, wallpapers, decorative decals or stickers,automobile detailing features or decals, and plastic or rubber “bumps”employed as feet, spacers, stops, or protectors on various articles, andany number of other applications where pressure sensitive adhesives areusefully employed. Additional materials such as glass or somerigid/brittle plastics or metals that are not traditionally used as tapesupports also have utility as some in some applications in conjunctionwith the adhesive compositions of the invention.

The width and length of the adhesive articles of the invention are notparticularly limited. In some embodiments, the adhesive articles of theinvention are converted to tape articles by slicing a coated sheet orfilm to widths of between about 0.25 cm and 10 cm, in some embodimentsbetween about 0.5 cm and 7.6 cm; however, the width of a tape article isnot particularly limited. Additionally, in some embodiments, theadhesive articles of the invention are suitably converted to smallsheets, for example 20 cm by 28 cm sheets, for use by a consumer. Insome embodiments, sheets are provided to a consumer who is then free todivide the sheet into the desired shape and dimensions for use in aspecific application.

It is an advantage of the invention that the adhesive articles of theinvention are masking articles, whether or not they are used as such. Inorder to be used as a masking article, any of the adhesive articlesdescribed are useful as such with no further modification. The adhesivearticles do not require an edge coating or other edge treatment prior tousing the adhesive article in a masking application. Thus, while thenecessity of adding an edge treatment effectively limits the utility ofedge-treated tapes to rectangular shapes, wherein the edge treatment isefficiently applied in a manufacturing process, such a limitation doesnot exist with the masking articles of the invention. Therefore, theshapes easily utilized in conjunction with the supports onto which theadhesive compositions of the invention are coated are virtuallyunlimited in terms of ease of manufacturing and even ease of the enduser in converting one supplied shape to a customized shape, for exampleby hand cutting with scissors, a box cutter, a hole punch, a die cutter,or any other cutting implement. Thus, for example, a consumer could buya 20 cm by 28 cm sheet of a masking tape of the invention and cut itinto the desired shape for a specific end use. Such end uses include,for example, stenciling or patterning wherein the adhesive article isemployed to mask an area to be painted and is removed after the paint isapplied.

In some embodiments, prior to coating and drying the adhesivecompositions of the invention on the support, the support ispre-treated. Pre-treatments are applied to, or carried out on, the majorsurface of the support onto which the adhesive composition will becoated, when an increase in the adhesive bonding between the support andthe adhesive composition is necessary to prevent failure of thesupport-adhesive interface when a tape article or other masking articleis removed from the surface onto which it was applied in use.Pre-treatments include coatings applied to the support surface. One ofskill will understand that the nature of such “primer” coatings isspecific to each support and specific adhesive composition, and a widevariety of such primer coatings are available—in fact, some supportmaterials are available pre-primed for this purpose. Another type ofsuitable pre-treatment is roughening the surface of the support prior tocoating, which increase surface area for adhesion by the coated adhesivecompositions of the invention. Yet another type of suitablepre-treatment is corona or plasma treatment of the surface to inducechemical changes that can increase adhesion of the adhesive compositionsof the invention to the support. While such pre-treatments are useful insome embodiments, it is an advantage of the cationically emulsifiedadhesive compositions of the invention that many suitable supports,including paper, polyethylene terephthalate, and polycarbonate, arecoated with the compositions in the absence of any type of pre-treatmentto improve bonding at the support-adhesive interface.

In some embodiments where the adhesive article is a tape, the major sideopposite the side of the support onto which the adhesive compositionwill be coated is treated in order to facilitate release of the adhesivefrom the major side opposite to the adhesive-coated side duringunwinding of the tape by the end user. Such coatings, often termed “lowadhesion backsize” or LAB in the industry, are well known by those ofskill and any of the conventionally employed LAB treatments and coatingsare suitably applied to the tape supports employed to form the maskingtape articles of the invention. We have found that such conventional LABtreatments are suitably employed in various embodiments of the inventionto provide tape articles having conventional values of unwind force, forexample between about 50 g/cm to 500 g/cm, or about 100 g/cm to 350 g/cmwhen measured at 180° peel at a rate of 228.6 cm/min and set time of 5seconds.

In some embodiments, the adhesive article includes a release liner. Forexample, in some embodiments, it is desirable to form the adhesivearticle in sheet form, or it is useful for some other reason to avoidhaving the adhesive article wound upon itself as is commonly done withadhesive tapes. For example, if the end use is a stenciling application,it is generally desirable to employ a release liner—that is, a separatesupport-type sheet or film—applied to the coated and dried adhesivecomposition residing on the support. In such embodiments, the support iscoated on one major side thereof with the adhesive composition, theadhesive composition is dried if necessary, and a release liner isapplied on top of the dried adhesive layer. The release liner is formedfrom, or coated with, a material that releases cleanly from the adhesivewhen peeled off by the end user, in embodiments transferringsubstantially no residue of the release liner material on or in theadhesive. Such release liners are well known by those of skill and anyof the conventionally employed release liners are suitably applied tothe tape supports employed to form the masking tape articles of theinvention.

In embodiments where the adhesive article is a tape article, theadhesive compositions of the invention are coated onto the selectedsupport at coating weights of about 5 g/m² to 90 g/m² of the driedadhesive composition on the support, or about 10 g/m² to 70 g/m², orabout 15 g/m² to 50 g/m² of the dried adhesive composition on thesupport. However, it will be understood that the adhesive articles ofthe invention are not limited to masking tape articles or to maskingapplications, and for various applications a thicker or thinner coatingof the adhesive is useful and is easily optimized by one of skill.

In some embodiments, the adhesive articles of the invention are edgecoated adhesive articles. In some such embodiments, the adhesivecompositions of the invention are employed as an edge coating inconjunction with an additional adhesive material on a support. Theadditional adhesive material is not particularly limitedcompositionally, but in some embodiments is a conventional masking tapeadhesive or other pressure-sensitive adhesive. In other embodiments theadditional adhesive is an adhesive composition of the invention thatdiffers compositionally from the edge coated composition. Thus, inembodiments, the major side of a support onto which an additionaladhesive is coated is further coated at the edges of the same major sidethereof with an adhesive composition of the invention. In some suchembodiments, the additional adhesive covers the entirety of the majorside, and an adhesive composition of the invention is coated on top ofthe additional adhesive. In other such embodiments, the additionaladhesive does not cover the entire width of the major side and theadhesive compositions of the invention are coated contiguous(side-by-side in touching relation to the additional adhesive. In stillother embodiments, the additional adhesive and the adhesive compositionof the invention are coated discontinuously, wherein the two adhesivematerials do not contact each other. In any such embodiment, the twoadhesive materials are suitably coated either contemporaneously orstepwise, in a single pass coating or in two separate passes.

It will be understood that some of the edge coated adhesive articlesdisclosed above, for example the contiguous or discontinuous coatings,usefully employ the adhesive compositions of the invention because thecompositions are pressure-sensitive adhesives, unlike conventional edgecoatings. For example, some conventional edge coatings aresuperabsorbents that are not pressure sensitive adhesives. Such edgecoatings are not suitably employed, e.g., in a discontinuous orcontiguous coating relative to a conventional masking tape adhesive,because the superabsorbent will not adhere to the masked surface andthus will not provide the protection afforded by the pressure sensitiveadhesives of the invention.

In some embodiments, the edge coated adhesive articles of the inventionhave no additional adhesive material coated onto the support. That is,the adhesive compositions of the invention are coated discontinuously ona major side of a support onto which no additional adhesive is coated.Pattern coating and stripe coating, as described above, are useful insome embodiments to provide an “edge-coated only” adhesive articlewherein one or both edges of a tape support are coated with the adhesivecomposition. Such articles have pressure sensitive adhesive performanceover only a portion of the major side that contacts a surface in amasking application, and no adhesion at all over the remainder thereof.In some embodiments, edge-coated only adhesive articles reduce the totalamount of coated material per unit of area in forming the tapeconstruction. In some embodiments, an edge-coated only adhesive articlehas a reduced adhesive force per unit of tape area, which in turn aidsin removing the article from a surface after application. In someembodiments, by using an edge-coated only masking article, a surface caneffectively be masked wherein adhesive does not contact, e.g., a verydelicate portion of the surface. Such articles are useful, for example,in highly sensitive applications such as artwork restoration, paintingof surfaces contiguous to delicate fabrics, painting of surfacescontiguous to very old woodwork having an original finish, or protectingsemiconductor surfaces during coating processes. Because in suchedge-coated only articles the edge coating is itself a pressuresensitive adhesive, such masking articles can be formed.

An additional advantage of the edge coated adhesive articles of theinvention is that the adhesive force of the edge coating (as evidencedby, e.g., peel adhesion level) is easily adjusted in the same manner asdescribed above for the supports coated entirely with the adhesivecompositions of the invention. Thus, for example, a masking article iseasily formed wherein the edges of the coated major side thereof have agreater or lesser amount of adhesive force to the intended substratecompared to the additional adhesive disposed on at least a portion ofthe remainder of the major side. Similarly, a masking article is easilyformed wherein the edges of the coated major side thereof have a greateror lesser amount of tack compared to the additional adhesive disposed onat least a portion of the remainder of the major side.

In various embodiments, the edge coated adhesive articles are suitablycoated with the adhesive compositions of the invention at coatingweights of about 1 g/m² to 90 g/m² of the dried adhesive composition, orabout 5 g/m² to 70 g/m², or about 10 g/m² to 50 g/m² of the driedadhesive composition. However, it will be understood that the edgecoated adhesive articles of the invention are not limited to maskingtape articles or to masking applications, and for various applications athicker or thinner coating of the adhesive composition is useful and iseasily optimized by one of skill. Further, the width of the edge coatingis not particularly limited; that is, the distance between the outeredge of the major coated surface and the inner edge of the edge coatingcan encompass any percent of the total width of the support that is lessthan 100%. In many embodiments, the edge coating encompasses between 5%and 50% of the total width of the support.

Examples of conventional masking tapes that are suitably edge coatedwith the adhesive compositions of the invention include SCOTCHBLUE® 2080or 2090, available from the 3M Company of St. Paul, Minn.

Edge coating of the adhesive compositions is suitably carried out usingany method known to those of skill. For example, stripe coating, knifecoating, brush coating, kiss coating, die coating, or curtain coatingare useful means to apply the adhesive compositions of the invention tothe edges of a support.

Applications of the Adhesive Articles

In various embodiments, the adhesive articles of the invention areapplied to a selected substrate, whereupon the adhesive compositionperforms as a pressure sensitive adhesive. Pressure-sensitive adhesivesare recognized as a standard class of materials. Pressure-sensitiveadhesives are generally recognized as having tack at temperaturesranging between about 15° C. to 25° C. and adhesion to a variety ofdissimilar surfaces upon mere contact without the need for more thanmanual pressure. Pressure sensitive adhesives require no activation bywater, solvent or heat in order to exert a strong adhesive holding forcetowards materials such as paper, cellophane, glass, plastic, wood andmetals. Pressure sensitive adhesives have a sufficiently cohesiveholding and elastic nature that, despite their aggressive tackiness,they can be handled with the fingers and removed from smooth surfaceswithout leaving a substantial residue (see, e.g., Test Methods forPressure-Sensitive Tapes, 6th Ed., Pressure Sensitive Tape Council,1953). Pressure sensitive adhesives and tapes are well known, and thewide range and balance of properties desired in such adhesives has beenwell analyzed (see, e.g., U.S. Pat. No. 4,374,883; and“Pressure-Sensitive Adhesives” in Treatise on Adhesion and AdhesivesVol. 2, “Materials,” R. I. Patrick, Ed., Marcel Dekker, Inc., N.Y.,1969).

Substrates on which the adhesive compositions of the invention have goodperformance as a pressure sensitive adhesive, when combined with asuitable support in an adhesive article, include, but are not limitedto, glass, metal, wood (including wood products such as cardboard orparticleboard), wallboard, synthetic or natural polymers includingfilled, colored, crosslinked or surface-modified polymers including, forexample, polyvinyl chloride, polyesters such as polyethyleneterephthalate or polylactic acid, natural or synthetic rubber,polyamides, polyolefins such as polyethylene or polypropylene, applianceor equipment casing materials such as acrylonitrile-butadiene-styrene(ABS) copolymers, polycarbonate, polymethyl methacrylate, and the like;and mixed or composite materials such as polymer-wood composites, andthe like, and any painted or primed surface thereof. Additionally, it isa feature of the adhesive compositions of the invention that adhesion toa selected surface is easily optimized to a desired level whilemaintaining the level of cationic and/or anionic monomer present in thecationic or zwitterionic polymer. For example, it is possible to adjustadhesion, as measured by PSTC-101, Test Method A (HarmonizedInternational Standard, Peel Adhesion of Pressure Sensitive Tape;available at http://www.pstc.org/files/public/101.pdf), between about 50g/cm and 450 g/cm using a constant level of cationic monomer and varyingthe type and ratio of the other monomers in the cationic or zwitterionicpolymer.

Once applied to the selected substrate surface, the adhesive articles ofthe invention are usefully employed in one or more masking applications.The performance of the adhesive articles of the invention as maskingarticles is characterized by the interaction of the adhesivecompositions of the invention with the liquid and/or liquid-borne solidmaterials applied to the masked substrate, wherein the interactionresults in the substantial prevention of contact by the liquid orliquid-borne materials with the masked surface. To use the maskingarticle to produce sharp, clean, smooth lines of separation between amasked substrate, which is shielded from a coating, and the unmaskedregion of the substrate to which a liquid coating is applied, theadhesive article is first adhered to the region of the substrate beshielded from the coating. Next, the coating is applied to the unmaskedregion of the substrate and applied to at least the edge of the adhesivearticle. The coating is then allowed to at least partially dry. Last,the adhesive article is removed from the substrate. Because the adhesivearticle inhibits the migration of the coating beyond the edge of themasked surface, a clear even line of demarcation is produced between thecoated region of the substrate and the masked surface of the substrate.

In many masking applications, the liquid coating applied to the maskedsubstrate is a paint formulation. Paint formulations are solid,semisolid, or liquid particles dispersed in a suspension, i.e., adispersion or an emulsion, typically though not always an aqueoussuspension. In many embodiments, paint formulations are emulsions thatare anionically stabilized. In some such embodiments, a paintformulation is a waterbased latex including one or more anionicallycharged water soluble polymers and dispersed inorganic pigmentparticles, wherein the pigment particles are kept in a dispersed stateby stabilizing effect of the one or more water soluble polymers. Inother embodiments, the paint is a waterbased latex formed by stabilizingpigment particles with one or more anionically charged surfactants inaddition to one or more water soluble polymers. In such embodiments, theadhesive compositions of the invention inhibit the flow of the paintformulation components onto the masked surface, which is the portion ofthe masked substrate contacting the adhesive composition. The adhesivecomposition impedes this flow by destabilizing the paint formulation,either by inducing aggregation of particles within the paintformulation, or by increasing the viscosity of the paint formulation,both of which mechanisms tend to form a barrier that impedes, orotherwise inhibits, the migration of the paint formulation beyond theedge of the interface of the masked substrate and the adhesivecomposition. The cationic monomer present in either the cationic polymeror the zwitterionic polymer of the adhesive composition interacts withthe anionic moieties of the paint formulation, causing the observedeffect.

In some embodiments, a liquid coating—whether a paint formulation orsome other liquid coating material—is cationically stabilized instead ofanionically stabilized such as the paint formulations described above.It is a feature of the invention that in embodiments wherein theadhesive article includes a zwitterionic polymer, such cationicallystabilized liquid coating compositions are effectively masked in thesame manner as an anionically stabilized waterborne latex is stabilized.That is, the anionic monomers present in the zwitterionic polymer induceaggregation by destabilization, or induce an increase in viscosity, byinteraction of the anionic monomers with the cationic moieties presentin the latex.

It is a feature of the adhesive articles of the invention that, becauseof the absence of an edge treatment, that adhesion upon application tothe selected substrate is always constant across the entire adhesivearticle. Edge treatments of the prior art masking tapes can affectadhesion where the tapes are applied and cause adhesion to be greater orlesser at the edges than over the remainder of the edge treated tape.Greater adhesion to the substrate can cause the tape to leave residueupon removal or prevent effective removal altogether, or even causedamage to the underlying substrate upon attempted removal. Lesseradhesion at the edges can cause lack of sufficient adhesion to thesubstrate, leading to loss of barrier properties at the edges of thetape and defeating the purpose of the edge treatment. The adhesivearticles of the invention do not have differential adhesion at the edgesbecause the adhesive composition itself is the barrier material and thebarrier material is present over the entire contact area of the adhesivecomposition and the masked surface.

Additionally, the masking performance of the adhesive compositions ofthe invention is characterized by the substantial absence of anyabsorption of the liquid coating applied to the masked substrate. Thatis, the adhesive articles do not perform in masking applications byabsorbing liquid. Testing of masking tape articles reveals no measurableswelling of the adhesive compositions when an adhesive article of theinvention is applied to a substrate and the substrate is coated withwaterbased paint formulations. The masking properties of the adhesivecompositions are therefore not achieved by any absorptive phenomena.

The masking properties of the adhesive articles of the invention work toproduce paint lines that have a lower degree of variability around acenter line defined by the edge of the masked surface than an edgedefined by a conventional masking tape. That is, all other variableremaining constant, an edge of a masked surface formed by applying anadhesive article of the invention on a selected substrate will produce apaint line having a lower degree of variability around a center linethan an edge provided by a standard masking tape. The center line anddegree of variability can be determined using known statisticaltechniques such as the method of least squares, linear regression, andanalysis of variance. Additionally, the masking properties of theadhesive articles of the invention work to produce paint lines that havethe same or lower degree of variability around a center line defined bythe edge of the masked surface than an edge defined by a masking tapehaving an edge treatment. That is, all other variable remainingconstant, an edge of a masked surface formed by applying an adhesivearticle of the invention on a selected substrate will produce a paintline having the same or lower degree of variability around a center linethan an edge provided by a commercial edge-treated masking tape.

Another aspect of the masking application is removal of the maskingarticle after the coating operation(s) are carried out. It is a featureof the adhesive articles of the invention that regardless of thesubstrate onto which the adhesive article is applied, removal issubstantially clean—that is, there is no observable residue left uponremoval of the article, and there is no damage to the substrate as aresult of removing the adhesive article. Importantly, there is noobservable residue left around the masked surface at the edge of themasked surface when the adhesive articles of the invention are removedfrom a substrate after carrying out a masking application. Withoutwishing to be limited by theory, we believe clean removal of theadhesive articles of the invention is due in part to maintenance of ahigh cohesive strength of the adhesive composition and high adhesivebonding between the adhesive composition and the support over theentirety of the adhesive article and further throughout application,masking, and removal of the adhesive article. Additionally, while notwishing to be limited by theory, we believe that preventing themigration of the liquid coating applied in a masking operation into theinterface defined as the masked surface, and preventing absorption ofany liquid as a means of preventing said migration, results inmaintaining the integrity of the adhesive article throughout the maskingapplication and results in easy, clean removal from the substrate afterthe masking is accomplished.

In order that the invention described herein can be more fullyunderstood, the following examples are set forth. It should beunderstood that these examples are for illustrative purposes only, andare not to be construed as limiting this invention in any manner.

EXPERIMENTAL Compounds

The following compounds, used in the various Examples, are referred tobelow using the abbreviations indicated in Table 1.

TABLE 1 Abbreviations and sources for compounds employed in theExamples. Abbreviation Compound Source DMAEA-C₁Cl Dimethylaminoethylacrylate CIBA, Marrietta, GA methyl chloride (2- trimethylammoniumethylacrylate chloride) DMAEMA-C₁₆Br Dimethylaminoethyl acrylate See Examplehexadecyl bromide VAc Vinyl Acetate Celanese Corp., Dallas, TX MAMethacrylic acid BASF Corp., Ludwigshafen, Germany AA Acrylic acid BASFCorp. NVP N-vinylpyrrolidinone ISP Chemicals, Inc., Calvary City, KYIBMA Isobutyl methacrylate Lucite International, Inc., Cordova, TN HPAHydroxy propyl acrylate Cyro Industries, Parsippany, NJ ODA Octadecylacrylate Cytec Industries, Inc., Woodland Park, NJ STA Stearyl acrylatePolysciences, Inc., Warrington, PA SiMac (MW) Polydimethylsiloxane ShinEtsu, Tokyo, Japan methacrylate; MW is for siloxane portion of monomerEtOH Ethanol J. T. Baker; Austin, TX BHT 2,6-Di-tert-4-methyl phenolSigma-Aldrich Co. MEHQ Hydroquinone monomethyl ether Alfa AesarVAZO ®-67 2,2-Azobis(2-methylbutyronitrile) E. I. du Pont de Nemours and(V-67) Co., Wilmington, DE V-50 2,2′-Azobis(2- Wako Pure Chemical Ind.,Ltd., (V-50) methylpropionamidine) Osaka, Japan dihydrochlorideETHOQUAD ® Cocoalkylmethyl[polyoxy-ethylene Akzo Nobel N.V., Amsterdam,C/25 (15)] ammonium chloride the Netherlands

General Procedures Procedure A. Polymer Synthesis—Water

A clean reaction bottle is charged with 84 parts by weight of thedesired monomer mixture, 0.5 parts of V-50 (obtained from Wako PureChemical Ind., Ltd., Osaka, Japan), and 300 parts of water. This mixtureis purged with nitrogen for 3 minutes. The reaction bottle is sealed andplaced in a 50° C. preheated water bath with a tumbling mechanism, andtumbled for 17 hours. Then the bottle is removed from the water bath andanother 0.1 parts of V-50 is added to the bottle, and the bottle ispurged and sealed as before. The bottle is placed back in the 50° C.water bath and tumbled for an additional 8 hours. In a typical reaction,percent solids analysis revealed about <0.5% unreacted monomer; that is,about >99.5% conversion of monomer.

Procedure B. Polymer Synthesis—Ethanol

A clean reaction bottle is charged with 60 parts by weight of thedesired monomer mixture, 0.5 parts of VAZO® 67 (obtained from duPontdeNemours and Co. of Wilmington, Del.), and 40 parts of ethanol. Thismixture is purged with nitrogen for 3 minutes. The reaction bottle issealed and placed in a 65° C. preheated water bath with a tumblingmechanism, and tumbled for 17 hours. Then the bottle is removed from thewater bath and another 0.1 parts of VAZO® 67 is added to the bottle, andthe bottle is purged and sealed as before. The bottle is placed back inthe 65° C. water bath and tumbled for an additional 8 hours. In atypical reaction, percent solids analysis revealed about <0.5% unreactedmonomer; that is, about >99.5% conversion of monomer.

Procedure C. Polymer Synthesis—Emulsion

A clean reaction vessel is charged with 40 parts by weight of thedesired monomer mixture, 60 parts by weight of water, and 2 parts byweight of ETHOQUAD® C-25 (obtained from Akzo Nobel N.V. of Amsterdam,the Netherlands). This mixture is stirred and purged with nitrogenthroughout the reaction. The mixture is heated to 50° C., then aninitiator mixture is added in a single addition to the vessel. Theinitiator mixture consists of 0.5 parts by weight of V-50 (obtained fromWako Pure Chemical Ind., Ltd., Osaka, Japan) and 2 parts by weight ofwater. After addition of the initiator mixture, the reaction vessel isstirred at 50° C. for about 8 hours, then another 0.1 parts by weight ofthe initiator mixture is added to the reaction vessel. The vessel isstirred at 50° C. for an additional 4 hours, and then a sample isremoved and analyzed using gas chromatography to determine the amount ofunreacted monomer. If less than 0.5 parts of unreacted monomer ispresent, the mixture is allowed to cool to room temperature.

In some cases, where the monomer mixture contains acrylic acid and/ormethacrylic acid, the cooled mixture is stirred and a 10% aq NaOH, KOH,LiOH or an amine solution is added, to adjust the final pH to betweenabout 4-7. Neutralization is noted where carried out.

Procedure D. Laboratory Scale Coating of Polymer on a Support

Polymers synthesized as described in Procedures A, B, or C above arecoated onto masking tape type supports for testing. Coating of thereaction mixtures are carried out as-is, that is, without isolation orany purification of the polymers synthesized. The reaction mixtures areknife coated onto the primed side of a 15.24 cm (6 inch) wide papersubstrate 5.4 mil (0.14 mm) thick unless otherwise stated, having adensity of 4.9 g/m² unless otherwise stated, and saturated with asuitable saturant, pretreated on one side with a suitable primer, andtreated on the reverse side with a suitable LAB, targeting a coatingweight of about 2.93 g/cm² to 3.14 g/cm² for the dry composition. Aftercoating, the coated supports are dried by placing in a forced convectionfloor modeloven (obtained from Despatch Industries of Minneapolis,Minn.) set to 93° C. for about 5 minutes. The coated, dried supports arereferred to as masking tape or masking tape articles.

Procedure E. Pilot Scale Coating of Polymer on a Support

Polymers synthesized as described in Procedures A, B, or C above arecoated onto masking tape type supports to create rolls of tape fortesting. Pilot scale coating of the reaction mixtures are carried outas-is, that is, without isolation or any purification of the polymerssynthesized. The reaction mixtures are knife coated onto the primed sideof a 15.24 cm (6 inch) wide paper substrate 5.4 mil (0.14 mm) thickunless otherwise stated, having a density of 4.9 g/m² unless otherwisestated, and saturated with a suitable saturant, pretreated on one sidewith a suitable primer, and treated on the reverse side with a suitableLAB, targeting a coating weight of about 2.93 g/cm² to 3.14 g/cm² forthe dry composition. Coated webs were dried using a 3-Zone airfloatation oven with temperatures set to 150° F., 175 ° F. and 250 ° F.respectively. Zone lengths were 9 feet, 9 feet and 18 feet and the webspeed was set at 15 feet per minute for all runs. Rolls of the coated,dried supports are referred to as masking tape or masking tape articles.

Procedure F. Testing of Masking Articles

The masking tapes are subjected to one or more of a variety of tests.Not every test is carried out on every masking tape. Control tapes usedfor comparison in various tests in include the following, as abbreviatedC1-C5 in the tests below. Not every test employs every control tape.

-   -   C1: SCOTCH-BLUE® 2020, available from 3M Company, St. Paul,        Minn.    -   C2: SCOTCH-BLUE® 2080, available from 3M Company, St. Paul,        Minn.    -   C3: SCOTCH-BLUE® 2090, available from 3M Company, St. Paul,        Minn.    -   C4: SCOTCH-BLUE® 2093, available from 3M Company, St. Paul,        Minn.

Peel adhesion of the masking tapes is measured using the procedure ofPSTC-101, Method A using glass or stainless steel substrates.

Transfer of adhesive to a substrate—that is, the amount of adhesive thatremains on a substrate after removing the tape—is measured visuallyusing the criteria set forth in Table 2. Substrates include glass andwallboard. Adhesive transfer is measured after a peel adhesion testingor after paint testing.

TABLE 2 System used for scoring adhesive transfer to a substrate aftertape removal. 0 No observable adhesive residue on substrate 1 Less than3 small patches of adhesive remain on substrate 2 Adhesive observed onsubstrate in 3-10 spots 3 Adhesive observed on substrate in >10 spots 4Adhesive observed over entire taped area after removal from substrate 5All adhesive remains on substrate, plus tape support is split uponattempted removal

Paint testing of the masking tapes is carried out on glass or wallboard.Surface preparation for glass is carried out by identifying the non-Sn(non-tin) side of a new 20.3 cm (8 inch) by 30.5 cm (12 inch) glasspanel using a black light, and cleaning the non-Sn side of the glasspanel with one wipe each of diacetone alcohol, heptane, and ethanol (inthe stated order) prior to testing; tape is applied to the cleanedsurface. The wallboard substrates are wiped with a dry cloth wipe priorto use, coated with one layer of latex primer followed by one layer ofwhite latex paint. Painted wallboard substrates were allowed to dryprior to tape application.

A 20.3 cm (8 inch) long strip of tape is gently applied by hand to thesubstrate. A 2.04 kg (4.5 pound), 4.45 cm (1.75 in) wide, calibratedrubber roller is centered horizontally relative to the width of the tapeand the roller is passed lengthwise back and forth by hand two times,for a total of four individual passes over the tape at a rate ofapproximately 30.5 cm (12 inches) per minute for a total of two passes.For testing on glass, paint is applied to the tape sample using a paintbrush and within 15 minutes of applying the tape to the panel. Fortesting on wallboard, paint is applied by paint roller, rolling in thedirection of the tape, and after a minimum of 1 hour after the tape isapplied to the panel. For both glass and wallboard, the painted testpanels are then allowed to dry at room temperature. Test paint used onglass is Sun Proof Exterior House & Trim Semi-Gloss Latex 100% Acrylicblack paint #78-851, available from Pittsburgh Paints, PPG Industries,Pittsburgh, Pa. (“PPG”). Test paint used on wallboard includes, but isnot limited to: Sherwin Williams Duration in black matte (“SW Dur”)available from the Sherwin Williams Co. of Cleveland, Ohio) SherwinWilliams Emerald in black matte (“SW Emerald”, available from theSherwin Williams Colo.), Behr Premium Performance Ultra in black flat(“Behr PPU”, available from Behr Paint Corporation of Santa Ana,Calif.), and Valspar Signature High Definition in black eggshell(“Valspar SHD”, available from Valspar Corporation of Minneapolis,Minn.). Three replicates of each tape sample are tested. Approximately15 feet of tape is removed from the tape roll between each test sample.After the paint is completely dry, the paint line performance for thetapes is evaluated visually.

The term used for observed encroachment of paint beyond the edge of themasking tape after coating with the paint indicated is “bleed”. Theamount of observable bleed on a glass or wallboard substrate is ratedaccording to Table 3. Intermediate scores between numbers, such as 0.5or 2.5, are also noted where appropriate.

TABLE 3 System used for scoring paint lines. 0 no observable bleed,acceptable paintline 1 Minimal bleed, acceptable paintline 2 Some bleed,may still be an acceptable paintline 3 Considerable bleed, not anacceptable paintline 4 Excessive bleed, not an acceptable paintline

Example 1

A clean reactor fitted with over head condenser, mechanical stirrer, andtemperature probe, was charged with 918 parts by weight of acetone, 807parts by weight of 1-bromohexadecane (n-hexadecyl bromide, C₁₆H₃₃Br),415.5 parts by weight of 2-(dimethylamino)ethyl methacrylate (DMAEMA),2.0 parts by weight of BHT, and 2.0 parts by weight of MEHQ. The mixturewas stirred at 150 rpm and 90/10 O_(2/)N₂ was purged through thesolution throughout the reaction. The mixture was heated to 74° C. for18 hours. A sample taken out for analysis by GC revealed a conversionof >98%. At this point 918 parts by weight of ethyl acetate was added tothe reaction vessel slowly, while stirring at very high speed. A whitesolid started to precipitate from the mixture. The reaction mixture wasallowed to cool to ambient temperature. The mixture was filtered toisolate the white solid precipitate and the precipitate was washed withabout 200 parts by weight of cold ethyl acetate. The precipitate wastransferred to a tray and dried in a vacuum oven at 40° C. for 8 hours.The dried precipitate was analyzed by NMR which revealed the presence ofa compound having the following structure.

The structure is referred to herein as DMAEMA-C₁₆Br, as noted above.

Examples 2-9

Using PROCEDURE A (water) or PROCEDURE B (ethanol), polymers weresynthesized from the monomers shown in Table 4. The polymers synthesizedaccording to PROCEDURE B were coated onto a paper backing employingPROCEDURE D. The polymers synthesized according to PROCEDURE A werecoated as follows.

The polymers in water were poured into clean glass molds dried at 93° C.in a forced convection oven for up to 30 minutes. The molds were allowedto cool to room temperature, and then the walls of the molds wereremoved to leave the dried adhesive on a flat glass plate. The paperbacking described in PROCEDURE D was placed on top of the driedadhesive, and the support was rolled four times using a 4.5 lb handroller. The supports were then peeled away, thereby removing theadhesive from the glass plate.

The tape articles were tested for paint line and adhesive transfer onglass according to PROCEDURE F. The results are shown in Table 5.

TABLE 4 Polymers synthesized according to PROCEDUREs A or B. Monomeramounts are expressed in weight ratios. Example No., DMAEA- DMAEMA-Procedure C₁Cl C₁₆Br AA AM-90G NVP IOA IBMA VAc 2, B 0 10 5 5 0 80 0 03, B 10 0 5 5 0 80 0 0 4, B 2 0 0 0 0 80 18 0 5, B 0 2 0 0 0 80 18 0 6,B 2 0 0 0 18 80 0 0 7, B 0 2 0 0 18 80 0 0 8, A 4 0 0 0 0 86 0 10 9, A10 0 2 0 0 78 0 10

TABLE 5 Paint line and adhesive transfer ratings for the polymers ofTable 4. Adhesive Example Paint Line Transfer No. Score, glass Score,glass Additional Observations 2 0.5 5 3 0 5 4 0.5 0 Difficult to peel -high adhesion 5 0.5 5 6 0.5 2 7 0 3 8 0.5 0 Easy to peel - moderateadhesion 9 0.5 2 Easy to peel - moderate adhesion C1 2 0 C2 0 0 C3 3 0C4 0.5 0

Examples 10-15

Using PROCEDURE C, polymers were synthesized from the monomers shown inTable 6 targeting 39 wt %-40 wt % solids in water; or using PROCEDURE B,targeted 60 wt %-61 wt % solids in ethanol. The polymers were coatedonto a paper support employing PROCEDURE D to form masking tapearticles. The masking tape articles were tested for paint line andadhesive transfer on glass and painted wallboard according to PROCEDUREF. The results are shown in Table 7. The masking tapes were tested forpeel adhesion to glass and stainless steel according to PROCEDURE F. Theresults are shown in Table 8.

TABLE 6 Polymers synthesized according to Procedures B or C. Amounts areexpressed in parts by weight. Example DMAEA- No. C₁Cl HPA VAc IOA IBMAMA 10 8 0 20 72 0 0 11 8 0 10 77 5 0 12 8 0 10 72 10 0 13 8 0 10 62 20 0 14¹ 8 10 10 72 0 0 15 8 0 10 72 0 10 ¹Precipitated - not coated ortested

TABLE 7 Paint line and adhesive transfer ratings for the polymers ofTable 6. Glass Painted Wallboard Example Paint Line Adhesive Paint LineAdhesive No. Score Transfer Score Score Transfer Score 10 1 0 1 0 11 0 00.5 0 12 0 0 0.5 —¹ 13 0 0 1 —¹ 15 0 0 0.5 —¹ C1 1 0 1 0 C2 0.5 0 1 0 C33 0 3 0 C4 0.5 0 1 0 ¹Peeled surface paper from wallboard.

TABLE 8 Peel adhesion of masking tape articles to glass and a paintedwood substrate (paint used was Sherwin Williams Super Paint, ExteriorAcrylic Latex in super white). Peel Adhesion, Example Peel Adhesion,painted No. glass, g substrate, g 10 1362.19 1664.68 11 1376.65 1540.2312 1341.78 1570.85 13 1426.83 1591.82 15 1204.57 1374.10 C1 1028.52972.67 C2 557.35 536.66 C3 408.80 357.20 C4 511.42 515.11

Examples 16-30

Using PROCEDURE C, polymers were synthesized employing 8 parts by weightof DMAEA-C₁Cl, and varying the monomer structure and content as shown inTable 9. All syntheses targeted 39 wt %-40 wt % solids in water.

TABLE 9 Polymers synthesized according to PROCEDURE C. Amounts areexpressed in parts by weight. DMAEA-C₁Cl was added in each case at 8parts by weight. Example SiMac No. VAc IOA AA MA 12K ODA STA 16 10 82 1720 72 18 30 62 19¹ 10 80 2 20¹ 10 80 2 21¹ 0 90 2 22 10 77 5 23 5 87 24²10 82 25 10 72 10 26 10 72 10 27 10 80 2 28 10 80 2 29 0 88 4 30 10 77 5¹KOH added according to PROCEDURE C. ²Additional surfactant added for atotal of 8 parts by weight of ETHOQUAD ® C25.

Before coating the emulsions, some were tested for shear instability.Using a stress-controlled rheometer (Model AR-G2 from TA Instruments ofNew Castle, Del.) each tested emulsion was subjected to a shear stressramp from 0 to 500 Pa over a period of 20 min at a constant temperatureof 25° C. Data collected was shear rate in reciprocal seconds (s⁻¹) as afunction of shear stress (Pa). A change in direction of the slope ofshear rate vs. shear stress indicates a change in the response of thesample to shear, or onset of shear instability. Onset of emulsioninstability as a function of shear for the tested emulsions is shown inTable 10.

TABLE 10 Onset of shear instability for polymer emulsions of Table 9.Example Onset of No. Instability, Pa 16 133 17 >200 18 150 23 96 24 11025 138 26 109.3 27 >200 28 160 29 142.6 30 137

The emulsions were coated onto a paper support employing PROCEDURE E toform masking tape articles. The masking tape articles were tested forpeel adhesion to glass and stainless steel according to PROCEDURE F. Insome cases, peel adhesion was further measured after 24 hours or 168hours on the glass or stainless steel substrate. The results are shownin Table 11.

TABLE 11 Peel adhesion from glass and stainless steel for the maskingtape articles formed from the polymers of Table 9. Glass (g); StainlessSteel (g); Example residence time (hr) residence time (hr) No. 0 24 1680 24 168 16 1004.99 — — 644.38 — — 17 915.69 — — 1020.87 — — 18 241.54 —— 201.56 — — 23 822.14 798.61 760.90 849.63 845.38 815.90 24 993.37782.45 862.96 1051.20 1016.61 1107.61 25 108.01 — — 143.45 — — 26 127.86— — 143.73 — — 27 972.39 833.76 1059.14 915.12 995.63 1102.51 28 1093.72968.14 1134.55 1135.40 1120.09 1230.37 29 725.75 721.49 712.42 1080.97848.50 1044.96 30 837.16 771.39 802.57 812.21 786.70 854.45 C1 1211.37 —— 840.85 — — C2 606.40 — — 573.51 — — C3 612.07 — — 581.73 — — C4 674.72— — 653.17 — —

The masking tape articles were tested for paint line on wallboardaccording to PROCEDURE F. Four test paints were used to score eachmasking tape formed from the polymers of Table 9. The results are shownin Table 12.

TABLE 12 Paint line analysis for the masking tape articles formed fromthe polymers of Table 9. Paintline on Painted Wallboard Paint SherwinBehr Valspar Example Line on Williams Premium Signature No. GlassEmerald Plus Ultra Hi-Def 16 2.0 4.0 3.0 3.5 17 2.0 4.0 2.5 3.0 18 1.03.7 2.5 2.0 23 0.5 2.0 2.0 1.5 24 1.0 3.5 2.5 2.0 25 4.0 4.0 3.0 4.0 264.0 4.0 3.0 4.0 27 1.0 2.2 2.5 2.5 28 0.5 1.5 2.5 2.0 29 1.0 2.0 2.5 2.030 3.0 3.2 3.0 3.5

Example 31

A polymer was formed using PROCEDURE C and having monomer content asfollows (in parts by weight): 8 DMAEA-C₁Cl; 10 VAc; 80 IOA; 2 MA. Totalsolids of the emulsion was 43.2 wt %. After completion ofpolymerization, the emulsion was divided into five portions; four of theportions were neutralized with different neutralizing agents to reach apH of about 6, and the fifth portion was not neutralized. Neutralizingagents used were KOH, NaOH, LiOH, and triethanolamine (TEA). The fiveportions were coated onto a paper support employing PROCEDURE E to formmasking tape articles. The masking tape articles were scored for paintline on glass and wallboard, and tested for peel adhesion on glass andstainless steel according to PROCEDURE F. The results are shown in Table13.

TABLE 13 Paint line scores and peel adhesion for the masking tapearticles formed from the polymer of Example 31. Paint line, Peel Peeladhesion Neut. Paint line, wallboard adhesion (g), (g), stainless Agentglass SW Emerald glass steel none 0 2.5 1404.43 1323.35 KOH 0 2.51533.14 1154.68 NaOH 0.5 2.5 1359.64 1331.01 LiOH 0.5 2 989.40 1257.87TEA 0 2 1284.80 1255.03

Examples 32 and 33

A polymer was formed using PROCEDURE C and having monomer content asfollows (in parts by weight): 8 DMAEA-C₁Cl; 5 VAc; 85 IOA; 2 MA. Totalsolids of the emulsion was 48 wt %. After completion of polymerization,the emulsion was divided into two portions. One portion, labeled Example32, was not neutralized and had a pH of about 2.5. The second portion,labeled Example 33, was neutralized with NaOH to a pH of about 6. Eachof the two emulsions was coated onto a standard crepe paper support anda “smooth structured” crepe paper support (“SS crepe”) employingPROCEDURE E to form masking tape articles. The masking tape articleswere scored for paint line on glass and wallboard, using three differenttest paints according to PROCEDURE F for wallboard. The paint used fortesting on glass was PPG. The results are shown in Table 14.

TABLE 14 Paint line scores on glass and wallboard for the masking tapesmade from the polymer emulsions of Examples 32 and 33. Paint Line PaintLine Score, Wallboard Example Score, SW Behr Valspar Backing No. GlassEmerald PPU S HD Crepe 32 1 2 2 3 33 1 2 2.5 3 SS Crepe 32 0.5 2 2 2.533 0.5 2 2 2.5 As C2 0.5 4 3 3 Supplied C4 0.5 3 2.5 3 C3 3 3 3 3 C1 12.5 2.5 3

The polymer emulsions of Examples 32 and 33, coated on both standard andsmooth structured crepe paper, were subjected to further paint lineanalysis using PROCEDURE F but on varnished oak and varnished pineboards. The results are shown in Table 15.

TABLE 15 Paint line scores on varnished pine and oak boards for themasking tapes made from the polymer emulsions of Examples 32 and 33.Paint Line Score Example No. Varnished Varnished (paper) Pine Oak 32(crepe) 0.5 0.5 33 (crepe) 0.5 0 32 (SS crepe) 0 0 33 (SS crepe) 0.5 0.5C2 0 1 C4 0 1 C3 0.5 2 C1 0.5 2

Examples 34-39

A polymer was formed using PROCEDURE C and having monomer content asfollows (in parts by weight): 8 DMAEA-C₁Cl; 5 VAc; 85 IOA; 2 MA. Totalsolids of the emulsion was 50 wt %. After completion of polymerization,the emulsion was divided into six portions. One portion, labeled Example34, was not neutralized and had a pH of about 2.5. The second throughsixth portions, labeled Examples 35 through 39, were each neutralizedwith NaOH to a pH of 4, 5, 5.5, 6 and 7 respectively. Each of the sixemulsions were coated onto a “smooth structured” crepe paper support(“SS crepe”) employing PROCEDURE E to form masking tape articles. Themasking tape articles were scored for paint line on glass and wallboard,using three different test paints according to PROCEDURE F forwallboard. The paint used for testing on glass was PPG. The results areshown in Table 16.

TABLE 16 Paint line scores on glass and wallboard for the masking tapesmade from the polymer emulsions of Examples 34 through 39. Paint LinePaint Line Score, Wallboard Example Score, SW Behr Valspar Backing No.Glass Emerald PPU S HD SS Crepe 34 0 2 1.5 2 35 0 2 1.5 1 36 0 2 1 2 370 2 1.5 1 38 0 2 1 1.5 39 0.5 2 1.5 2 As C1 1 1 1.5 2 supplied C2 0 4 44 C3 2 2.5 3 3 C4 0 2.5 1.5 2.5 C5 0.5 0 0.5 0.5

The polymer emulsions of Examples 34 through 39, coated on smoothstructured crepe paper, were further tested for peel adhesion on glassand stainless steel according to PROCEDURE F under two differentenvironmental conditions: (1) 21° C./20% RH and (2) 21° C./50% RH. Theresults are shown in Table 17.

TABLE 17 Peel adhesion from glass and stainless steel at 21° C./20% RHand 21° C./50% RH for the masking tape articles formed from the polymers34 through 39. Peel adhesion (g), Peel adhesion (g), Example glassstainless steel No. 20% RH 50% RH 20% RH 50% RH 34 1113.57 1399.051426.55 1358.79 35 1309.75 1384.59 1377.50 1358.22 36 1295.86 1437.601262.40 1327.61 37 1232.64 1337.53 1317.68 1300.96 38 1283.95 1381.471341.78 1281.96 39 1142.48 1298.12 953.96 1259.28

The present invention may suitably comprise, consist of, or consistessentially of, any of the disclosed or recited elements. As usedherein, the term “consisting essentially of” does not exclude thepresence of additional materials which do not significantly affect thedesired characteristics of a given composition or product.

The invention illustratively disclosed herein can be suitably practicedin the absence of any element which is not specifically disclosedherein. The various embodiments described above are provided by way ofillustration only and should not be construed to limit the claimsattached hereto. It will be recognized that various modifications andchanges may be made without following the example embodiments andapplications illustrated and described herein, and without departingfrom the true spirit and scope of the following claims.

We claim:
 1. A method of making a masking article wherein the article iscapable of substantially preventing one or more liquids or liquid-bornematerials from contacting a masked surface, the method comprising a.forming a reaction mixture comprising one or more cationic surfactantsand about 15 wt % to 60 wt % monomers in water, wherein the monomersconsist essentially of i. about 0 parts by weight to 5 parts by weightof acrylic acid, methacrylic acid, a carboxylate salt thereof, or amixture of two or more thereof, wherein the amount of carboxylate saltis determined based on the weight of the corresponding free acid; ii.about 50 parts by weight to 95 parts by weight based on the total weightof the polymer of an acrylate or methacrylate ester of an alcohol havingbetween 8 and 12 carbons; iii. about 2 parts by weight to 45 parts byweight based on the total weight of the polymer of an acrylate ormethacrylate ester including an alkylammonium functionality; iv. about 0parts by weight to 30 parts by weight based on the total weight of thepolymer of vinyl acetate, isobutyl acrylate, or a mixture of two or morethereof; and v. about 0 parts by weight to 2 parts by weight based onthe total weight of the polymer of a crosslinker; b. polymerizing themonomers to form a polymerized mixture, c. coating the mixture onto asupport, and d. drying the coated mixture.
 2. The method of claim 1wherein the one or more cationic surfactants includes at least onehaving quaternary ammonium functionality.
 3. The method of claim 1wherein the reaction mixture further comprises a thermal initiator andthe polymerizing is accomplished by heating the reaction mixture to atemperature of about 40° C. to 80° C.
 4. The method of claim 1 furthercomprising neutralizing the polymerized mixture to a pH of about 4 to 7.5. The method of claim 1 wherein the coating is accomplished by diecoating, knife coating, curtain coating, flood coating, spray coating,or cast coating.
 6. The method of claim 1 wherein the support comprisesa flat paper, a smooth paper, a textured paper, a natural polymer film,a synthetic polymer film, a natural polymer nonwoven, a syntheticpolymer nonwoven, a fabric reinforced film, a fiber or yarn reinforcedfilm, a fiber or yarn reinforced nonwoven, multiple layeredconstructions thereof, and laminated constructions thereof.
 7. Themethod of claim 1 wherein the masked surface comprises glass, metal,wood, wallboard, polyvinyl chloride, a polyester, a natural or syntheticrubber, a polyamide, a polyolefin, acrylonitrile-butadiene-styrenecopolymer, a polycarbonate, polymethyl methacrylate, a mixture orcomposite thereof, or a painted or primed surface thereof.
 8. Anadhesive composition, the composition comprising one or more surfactantsat least one of which has quaternary ammonium functionality and apolymer, the polymer consisting essentially of the polymerized productof a. 0.2 wt % to 5 wt % based on the total weight of the polymer ofacrylic acid, methacrylic acid, a carboxylate salt thereof, or a mixtureof two or more thereof, wherein the amount of carboxylate salt isdetermined based on the weight of the corresponding free acid; b. 50 wt% to 95 wt % based on the total weight of the polymer of an acrylate ormethacrylate ester of an alcohol having between 8 and 12 carbons, or amixture of two or more thereof; c. 2 wt % to 45 wt % based on the totalweight of the polymer of an acrylate or methacrylate ester having analkylammonium functionality; d. 0 wt % to 30 wt % based on the totalweight of the polymer of vinyl acetate, isobutyl acrylate, N-vinylpyrrolidone, or a mixture of two or more thereof; and e. 0 wt % to 2 wt% based on the total weight of the polymer of a crosslinker.
 9. Theadhesive composition of claim 8 wherein the polymer and the one or moresurfactants together comprise 15 wt % to 60 wt % of the composition andthe composition further comprises water.
 10. The adhesive composition ofclaim 8, wherein the acrylate or methacrylate ester having analkylammonium functionality is present in the polymer at 2 wt % to 12 wt% based on the total weight of the polymer.
 11. The adhesive compositionof claim 10, wherein the acrylate or methacrylate ester having analkylammonium functionality is present in the polymer at 2 wt % to 4 wt% based on the total weight of the polymer.
 12. The adhesive compositionof claim 8 wherein the carboxylate salt of acrylic acid or methacrylicacid is a sodium salt.
 13. The adhesive composition of claim 8 whereinthe acrylate or methacrylate ester of an alcohol having between 8 and 12carbons is isooctyl acrylate.
 14. The adhesive composition of claim 8wherein the acrylate or methacrylate ester including an alkylammoniumfunctionality is the reaction product of 2-(dimethylamino)ethyl acrylateor 2-(dimethylamino)ethyl methacrylate with an alkyl bromide or an alkylchloride having between 1 and 24 carbon atoms.
 15. The adhesivecomposition of claim 8 wherein the acrylate or methacrylate esterincluding an alkylammonium functionality is 2-(trimethylammonium)ethylmethacrylate chloride.
 16. The adhesive composition of claim 8 whereinthe polymer consists essentially of 85 wt % to 95 wt % based on thetotal weight of the polymer of an acrylate or methacrylate ester of analcohol having between 8 and 12 carbons.
 17. The adhesive composition ofclaim 8 wherein the polymer consists essentially of the polymerizedproduct of sodium methacrylate, isooctyl acrylate,2-(trimethylammonium)ethyl methacrylate chloride, and vinyl acetate. 18.An adhesive article comprising a support having first and second opposedmajor surfaces, and an adhesive composition according to claim 8disposed on at least a portion of at least one of the first and secondopposed major surfaces.
 19. The adhesive article of claim 18, andfurther comprising a paint formulation applied to at least a portion ofthe support; wherein the article inhibits the migration of the paintbeyond an edge of an interface at least partially defined by theadhesive composition.
 20. The adhesive article of claim 19, and furthercomprising a low adhesion backsize coating on the second major surface.